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{{Italic title}}
{{Other uses}}
{{Distinguish|Kaon}}
{{short description|story, dialogue, question, or statement used in Zen practice}}
{{Zen Buddhism}}
{{buddhism}}
{{nihongo|'''''Kōan'''''|公案}} ({{IPAc-en|ˈ|k|oʊ|æ|n|,_|-|ɑː|n}};<ref>{{cite LPD|3}}</ref> {{zh|c=公案|p=gōng'àn}}, {{IPAc-cmn|g|ong|1|-|an|4}}; {{lang-ko|화두}}, ''whadoo''; {{lang-vi|công án}}) is a [[narrative|story]], [[dialogue]], question, or statement which is used in [[Zen]] practice to provoke the "great doubt" and to practice or test a student's progress in Zen.

==Etymology==
The Japanese term ''kōan'' is the [[on'yomi|Sino-Japanese reading]] of the Chinese word ''gong'an'' ({{zh|c=[[wikt:公案|公案]]|p=gōng'àn|w=''kung-an''|l=public case}}). The term is a [[compound (linguistics)|compound]] word, consisting of the [[Chinese character|characters]] {{lang|zh|[[wikt:公|公]]}} "public; official; governmental; common; collective; fair; equitable" and {{lang|zh|[[wikt:案|案]]}} "table; desk; (law) case; record; file; plan; proposal."

According to the [[Yuan dynasty]] Zen master [[Zhongfeng Mingben]] ({{lang|zh|中峰明本}} 1263–1323), ''gōng'àn'' originated as an abbreviation of ''gōngfǔ zhī àndú'' ({{lang|zh|公府之案牘}}, Japanese ''kōfu no antoku''—literally the ''andu'' "official correspondence; documents; files" of a ''gongfu'' "government post"), which referred to a "public record" or the "case records of a public law court" in [[Tang dynasty]] China.{{sfn|Sasaki|1965|p=4-6}}{{sfn|Foulk|2000|p=21-22}}{{refn|group=note|Assertions that the literal meaning of ''kung-an'' is the table, desk, or bench of a magistrate appear on page 18 of Foulk 2000. See also {{sfn|McRae|2003|p=172–173, note 16}}}} ''Kōan/gong'an'' thus serves as a [[metaphor]] for principles of reality beyond the private opinion of one person, and a teacher may test the student's ability to recognize and understand that principle.

Commentaries in kōan collections bear some similarity to judicial decisions that cite and sometimes modify precedents. An article by T. Griffith Foulk claims
{{quote|...Its literal meaning is the 'table' or 'bench' ''[[An (Shintō)|an]]'' of a 'magistrate' or 'judge' ''[[gong (title)|kung]]''.{{sfn|Foulk|2000|p=21–22}}}}

''Gong'an'' was itself originally a metonym—an article of furniture involved in setting legal precedents came to stand for such precedents. For example, ''Di Gong'an'' ({{lang|zh|狄公案}}) is the original title of ''[[Celebrated Cases of Judge Dee]]'', the famous Chinese [[detective novel]] based on a historical Tang dynasty judge. Similarly, Zen kōan collections are public records of the notable sayings and actions of Zen masters and disciples attempting to pass on their teachings.

==Origins and development==

===China===

====Commenting on old cases====
Gong'ans developed during the [[Tang dynasty]] (618–907){{sfn|Schlütter|2008|p=111}} from the recorded sayings collections of Chán-masters, which quoted many stories of "a famous past Chán figure's encounter with disciples or other interlocutors and then offering his own comment on it".{{sfn|Schlütter|2008|p=109}} Those stories and the accompanying comments were used to educate students, and broaden their insight into the Buddhist teachings.

Those stories came to be known as gongan, "public cases".{{sfn|Schlütter|2008|p=109}} Such a story was only considered a gongan when it was commented upon by another Chán-master.{{sfn|Schlütter|2008|p=109}} This practice of commenting on the words and deeds of past masters confirmed the master's position as an awakened master in a lineage of awakened masters of the past.{{sfn|Schlütter|2008|p=1109}}

====Literary practice====
Koan practice developed from a literary practice, styling snippets of encounter-dialogue into well-edited stories. It arose in interaction with "educated literati".{{sfn|McRae|2003|p=131}} There were dangers involved in such a literary approach, such as ascribing specific meanings to the cases.{{sfn|McRae|2003|p=131}} Dahui Zonggao is even said to have burned the woodblocks of the ''[[Blue Cliff Record]]'', for the hindrance it had become to study of Chán by his students.{{sfn|Yampolski|2003a|p=20}} Kōan literature was also influenced by the pre-Zen Chinese tradition of the "literary game"—a competition involving improvised poetry.{{sfn|Hori|2003|p=Chapter 4}}

The style of writing of Zen texts has been influenced by "a variety of east Asian literary games":{{sfn|Heine|2008|p=52}}
{{quote|
#The extensive use of [[allusion]]s, which create a feeling of disconnection with the main theme;
#Indirect references, such as titling a poem with one topic and composing a verse that seems on the surface to be totally unrelated;
#Inventive wordplay based on the fact that [[Hanzi]] (Chinese characters) are homophonic and convey multiple, often complementary or contradictory meanings;
#Linking the verses in a sustained string based on hidden points of connection or continuity, such as seasonal imagery or references to myths and legends.{{sfn|Heine|2008|p=52}}}}

====Observing the phrase====
During the [[Song dynasty]] (960–1297) the use of gongans took a decisive turn. [[Dahui Zonggao]] (1089–1163){{refn|group=note|{{lang|zh|大慧宗杲}}; Wade-Giles: ''Ta-hui Tsung-kao''; Japanese: ''Daie Sōkō''}} introduced the use of ''kanhua'', "observing the phrase". In this practice students were to observe (''kan'') or concentrate on a single word or phrase (''huatou''), such as the famous ''mu'' of the [[Mu (negative)|mu-koan]].{{sfn|Griffith Foulk|2000|p=22}}

In the eleventh century this practice had become common.{{sfn|Schlütter|2008|p=111}} A new literary genre developed from this tradition as well. Collections of such commented cases were compiled which consisted of the case itself, accompanied by verse or prose commentary.{{sfn|Schlütter|2008|p=110}}

Dahui's invention was aimed at balancing the [[Vipassana|insight]] developed by reflection on the teachings with developing [[samatha]], calmness of mind.{{sfn|Griffith Foulk|2000|p=23}} Ironically, this development became in effect ''silent illumination'',{{sfn|Wright|2000|p=208}} a "[re-absorbing] of koan-study into the "silence" of meditation (''ch'an'')".{{sfn|Wright|2000|p=209}} It led to a rejection of Buddhist learning:
{{quote|Some extent of Buddhist learning could easily have been recognized as a precondition for [[Subitism|sudden awakening]] in Chan. Sung masters, however, tended to take the rejection literally and nondialectically. In effect, what they instituted was a form of Zen fundamentalism: the tradition came to be increasingly anti-intellectual in orientation and, in the process, reduced its complex heritage to simple formulae for which literal interpretations were thought adequate.{{sfn|Wright|2000|p=209–210}}}}

This development left Chinese Chan vulnerable to criticisms by neo-Confucianism, which developed after the Sung Dynasty. Its anti-intellectual rhetoric was no match for the intellectual discourse of the neo-Confucianists.{{sfn|Wright|2000|p=210–211}}

====Interaction====
The recorded encounter dialogues, and the koan collections which derived from this genre, mark a shift from solitary practice to interaction between master and student:
{{quote|The essence of [[Enlightenment in Buddhism|enlightenment]] came to be identified with the interaction between masters and students. Whatever insight [[Dhyāna in Buddhism|dhyana]] might bring, its verification was always interpersonal. In effect, enlightenment came to be understood not so much as an insight, but as a way of acting in the world with other people{{sfn|Kasulis|2003|p=30}}}}

This mutual enquiry of the meaning of the encounters of masters and students of the past gave students a role model:
{{quote|One looked at the enlightened activities of one's lineal forebears in order to understand one's own identity [...] taking the role of the participants and engaging in their dialogues instead{{sfn|McRae|2003|p=130}}{{refn|group=note|This role-taking is described by the Swedish psychologist of religion [[Hjalmar Sundén]], though McRae does not seem to be aware of this}}}}

Kōan training requires a qualified teacher who has the ability to judge a disciple's depth of attainment. In the [[Rinzai school|Rinzai Zen school]], which uses kōans extensively, the teacher certification process includes an appraisal of proficiency in using that school's extensive kōan curriculum.

====Contemporary koan-use====
In China and Korea, "observing the phrase" is still the sole form of koan-practice, though [[Seung Sahn]] used the Rinzai-style of koan-practice in his [[Kwan Um School of Zen]].{{sfn|Lachs|2012}}

===Japan===
Japanese Zen, both Rinzai and [[Sōtō]], took over the use of koan-study and commenting. In Sōtō-Zen, koan commentary was not linked to seated meditation.{{sfn|Griffith Foulk|2000|p=25}}

====Koan manuals====
When the Chán-tradition was introduced in Japan, Japanese monks had to master the Chinese language and specific expressions used in the koan-training. The desired "spontaneity" expressed by enlightened masters required a thorough study of Chinese language and poetry.{{sfn|Bodiford|2006|p=92–93}} Japanese Zen imitated the Chinese "syntax and stereotyped norms".{{sfn|Bodiford|2006|p=93}}

In the officially recognized monasteries belonging to the [[Five Mountain System|Gozan]] (Five Mountain System) the Chinese system was fully continued. Senior monks were supposed to compose Chinese verse in a complex style of matched counterpoints known as ''bienli wen''. It took a lot of literary and intellectual skills for a monk to succeed in this system.{{sfn|Bodiford|2006|p=94}}

The [[Five Mountain System#The Rinka|Rinka-monasteries]], the provincial temples with less control of the state, laid less stress on the correct command of the Chinese cultural idiom. These monasteries developed "more accessible methods of koan instruction".{{sfn|Bodiford|2006|p=94}} It had three features:{{sfn|Bodiford|2006|p=94}}
#A standardized koan-curriculum;
#A standardized set of answers based on stereotypes Chinese sayings;
#A standardized method of secretly guiding students through the curriculum of koan and answers.

By standardizing the koan-curriculum every generation of students proceeded to the same series of koans.{{sfn|Bodiford|2006|p=94}} Students had to memorize a set number of stereotyped sayings, ''agyō'', "appended words".{{sfn|Bodiford|2006|p=96–97}} The proper series of responses for each koan were taught by the master in private instruction-sessions to selected individual students who would inherit the dharma lineage.{{sfn|Bodiford|2006|p=97–98}}

''Missanroku'' and ''missanchō'', "Records of secret instruction" have been preserved for various Rinzai-lineages. They contain both the koan-curricula and the standardized answers.{{sfn|Bodiford|2006|p=98}}{{refn|group=note|In 1916 Tominaga Shūho, using the pseudonym "Hau Hōō", published a critique of the Rinzai koan-system, ''Gendai sōjizen no hyōron'', which also contained a translation of a ''missanroku''. The missanroku part has been translated by [[Yoel Hoffmann]] as ''"The Sound of the One Hand"'' (see {{sfn|Hoffmann|1975}}).{{sfn|Bodiford|1993|p=264, note 29}}}} In Sōtō-Zen they are called ''monsan'', an abbreviation of ''monto hissan'', "secret instructions of the lineage".{{sfn|Bodiford|2006|p=98}} The ''monsan'' follow a standard question-and-answer format. A series of questions is given, to be asked by the master. The answers are also given by the master, to be memorized by the student.{{sfn|Bodiford|2006|p=102–106}}

====Contemporary koan curricula====
In the eighteenth century the Rinzai school became dominated by the legacy of [[Hakuin]], who laid a strong emphasis on koan study as a means to gain [[kensho]] and develop insight.{{sfn|Griffith Foulk|2000|p=25}} There are two curricula used in Rinzai, both derived from the principal heirs of Rinzai: the Takuju curriculum, and the Inzan curriculum.{{sfn|Hori|2000}} According to [[Ama Samy|AMA Samy]], "the koans and their standard answers are fixed."{{sfn|Samy|2012|p=4}}

====Suppression in the Sōtō-school====
During the late eighteenth and nineteenth century the tradition of koan-commentary became suppressed in the Sōtō-school, due to a reform movement that sought to standardise the procedures for [[dharma transmission]].{{sfn|Griffith Foulk|2000|p=25}} One reason for suppressing the koan-tradition in the Sōtō-school may have been to highlight the differences with the Rinzai-school, and create a clear identity.{{sfn|Griffith Foulk|2000|p=25}} This movement also started to venerate [[Dogen]] as the founding teacher of the Sōtō-school. His teachings became the standard for the Sōtō-teachings, neglecting the fact that Dogen himself made extensive use of koan-commentary.{{sfn|Griffith Foulk|2000|p=25}}

==Doctrinal background==
The popular western understanding sees ''kōan'' as referring to an unanswerable question or a [[meaningless statement]]. However, in Zen practice, a kōan is not meaningless, and not a riddle or a puzzle. Teachers do expect students to present an appropriate response when asked about a kōan.{{sfn|Sasaki|1965|p=xi}}{{sfn|Hagen|2000}}{{sfn|Aitken|1991|p=xiii, 26, and 212}} {{sfn|Loori|1994|p=p64}}

Koans are also understood as pointers to an unmediated "Pure Consciousness", devoid of cognitive activity.{{sfn|Hori|2000|p=282}} Victor Hori criticizes this understanding:
{{quote|[A] pure consciousness without concepts, if there could be such a thing, would be a booming, buzzing confusion, a sensory field of flashes of light, unidentifiable sounds, ambiguous shapes, color patches without significance. This is not the consciousness of the enlightened Zen master.{{sfn|Hori|2000|p=284}}}}

According to Hori, a central theme of many koans is the 'identity of opposites':{{sfn|Hori|2000|p=289-290}}{{sfn|Hori|2000|p=310 note 14}}
{{quote|[K]oan after koan explores the theme of nonduality. Hakuin's well-known koan, "Two hands clap and there is a sound, what is the sound of one hand?" is clearly about two and one. The koan asks, you know what duality is, now what is nonduality? In "What is your [[original face]] before your mother and father were born?" the phrase "father and mother" alludes to duality. This is obvious to someone versed in the Chinese tradition, where so much philosophical thought is presented in the imagery of paired opposites. The phrase "your original face" alludes to the original nonduality.{{sfn|Hori|2000|p=289-290}}}}

Comparable statements are: "Look at the flower and the flower also looks"; "Guest and host interchange".{{sfn|Hori|2000|p=289}}

==Koan-practice==
Study of kōan literature is common to all schools of Zen, though with varying emphases and curricula.{{sfn|Ford|2006|p=35-43}} The Rinzai-school uses extensive koan-curricula, checking questions, and ''jakogo'' ("capping phrases", quotations from Chinese poetry) in its use of koans.{{sfn|Hori|2006}} The [[Sanbo Kyodan]], and its western derivates of [[Taizan Maezumi]] and the [[White Plum Asanga]], also use koan-curricula, but have omitted the use of capping phrases.{{sfn|Ford|2006|p=35-43}} In [[Chinese Chán]] and Korean Seon, the emphasis is on [[Hua Tou]], the study of one koan throughout one's lifetime.{{sfn|Lachs|2012}} In Japanese [[Sōtō Zen]], the use of koans has been abandoned since the late eighteenth and nineteenth century.{{sfn|Mohr|2000|p=245}}

===Hua-tou or breakthrough-koan===
In the Rinzai-school, the Sanbo Kyodan, and the White Plum Asanga, koan practice starts with the assignment of a ''hosshi'' or "break-through koan", usually the [[Mu (negative)#The Mu-kōan|mu-koan]] or "the sound of one hand clapping".{{sfn|Hori|2000}} In Chinese Chán and Korean Seon, various koan can be used for the hua-tou practice.

Students are instructed to concentrate on the "word-head", like the phrase "mu". In the Wumenguan (Mumonkan), public case No. 1 ("Zhaozhou's Dog"), Wumen (Mumon) wrote:
{{quote|... concentrate yourself into this 'Wú' ... making your whole body one great inquiry. Day and night work intently at it. Do not attempt nihilistic or dualistic interpretations."{{sfn|Shibayama|1974}}}}

Arousing this great inquiry or "Great Doubt" is an essential element of kōan practice. It builds up "strong internal pressure (''gidan''), never stopping knocking from within at the door of [the] mind, demanding to be resolved".{{sfn|Sekida|1985|p=138–139}} To illustrate the enormous concentration required in kōan meditation, Zen Master Wumen commented,
{{quote|It is like swallowing a red-hot iron ball. You try to vomit it out, but you can't.}}

Analysing the koan for its literal meaning won't lead to insight, though understanding the context from which koans emerged can make them more intelligible. For example, when a monk asked Zhaozhou (Joshu) "does a dog have Buddha-nature or not?", the monk was referring to the understanding of the teachings on [[Buddha-nature]], which were understood in the Chinese context of absolute and relative reality.{{sfn|Shibayama|1974|p=Commentary on case No. 1}}{{sfn|Swanson|1997}}{{refn|group=note|The controversy over whether all beings have the potential for enlightenment is even older. Vigorous controversy still surrounds the matter of Buddha nature. See "Tao-sheng's Theory of Sudden Enlightenment", Whalen Lai, in ''Sudden and Gradual'' (subtitle) ''Approaches to Enlightenment in Chinese Thought'', p. 173 and 191. The latter page documents how in 429 or thereabouts (more than 400&nbsp;years before Zhaozhou), Tao-sheng was expelled from the Buddhist monastic community for defending the idea that incorrigible persons (''icchantika'') do indeed have Buddha-nature (''fo-hsing'').}}

===Insight===
The continuous pondering of the break-through koan (''shokan''{{sfn|Hori|2005b|p=132}}) or [[Hua Tou]], "word head",{{sfn|Ford|2006|p=38}} leads to [[kensho]], an initial insight into "seeing the [[Buddha-nature|(Buddha-)nature]].{{sfn|Hori|2000|p=287}}

The aim of the break-through koan is to see the "nonduality of subject and object":{{sfn|Hori|2000|p=289-290}}{{sfn|Hori|2000|p=310 note 14}}
{{quote|The monk himself in his seeking is the koan. Realization of this is the insight; the response to the koan [...] Subject and object - this is two hands clapping. When the monk realizes that the koan is not merely an object of consciousness but is also he himself as the activity of seeking an answer to the koan, then subject and object are no longer separate and distinct [...] This is one hand clapping.{{sfn|Hori|2000|p=288-289}}}}

Various accounts can be found which describe this "becoming one" and the resulting breakthrough:
{{quote|I was dead tired. That evening when I tried to settle down to sleep, the instant I laid my head on the pillow, I saw: "Ah, this outbreath is Mu!" Then: the in-breath too is Mu!" Next breath, too: Mu! Next breath: Mu, Mu! "Mu, a whole sequence of Mu! Croak, croak; meow, meow - these too are Mu! The bedding, the wall, the column, the sliding-door - these too are Mu! This, that and everything is Mu! Ha ha! Ha ha ha ha Ha! that roshi is a rascal! He's always tricking people with his 'Mu, Mu, Mu'!...{{sfn|Satomi|King|1993|p=106}}{{refn|group=note|[[Maura O'Halloran]] also gives an account of herself becoming mu.{{sfn|O'Halloran|2007|p=78}}}}}}

But the use of the mu-koan has also been criticised. According to [[Ama Samy|AMA Samy]], the main aim is merely to "'become one' with the koan".{{sfn|Samy|2012|p=5}} Showing to have 'become one' with the first koan is enough to pass the first koan.{{sfn|Samy|2012|p=5}} According to Samy, this is not equal to [[Wisdom in Buddhism|prajna]]:
{{quote|The one-pointed, non-intellectual concentration on the hua-t’ou (or Mu) is a pressure-cooker tactics, a reduction to a technique which can produce some psychic experiences. These methods and techniques are forced efforts which can even run on auto-pilot. They can produce experiences but not prajana wisdom. Some speak of ‘investigating’ the hua-t’ou, but it is rather a matter of concentration, which sometimes can provide insights, yet no more than that.{{sfn|Samy|2012|p=5}}}}

===Testing insight – or learning responses===

====Sassho – Checking questions====
Teachers may probe students about their kōan practice using ''sassho'', "checking questions" to validate their [[satori]] (understanding) or [[kenshō|kensho]] (seeing the nature).{{sfn|Hori|2006|p=132–133}} For the ''mu-koan'' and the ''clapping hand-koan'' there are twenty to a hundred checking questions, depending on the teaching lineage.{{sfn|Hori|2006|p=133}} The checking questions serve to deepen the insight of the student, but also to test his or her understanding.{{sfn|Hori|2006|p=133}}

Those checking questions, and their answers, are part of a standardised set of questions and answers.{{sfn|Hoffmann|1975}}{{sfn|Stephenson|2005}}{{sfn|Samy|2012|p=5}} Students are learning a "ritual performance",{{sfn|Stephenson|2005}} learning how to behave and respond in specific ways,{{sfn|Hoffmann|1975}}{{sfn|Stephenson|2005}}{{sfn|Samy|2012|p=5}} learning "clever repartees, ritualized language and gestures and be submissive to the master’s diktat and arbitration."{{sfn|Samy|2012|p=5}}

====Jakugo – Capping phrases====
In the Rinzai-school, passing a koan and the checking questions has to be supplemented by ''[[jakugo]]'', "capping phrases", citations of Chinese poetry to demonstrate the insight.{{sfn|Hori|1999}}{{sfn|Hori|2003}} Students can use collections of those citations, instead of composing poetry themselves.{{sfn|Hori|1999}}{{sfn|Hori|2003}}

===Post-satori practice===
After the initial insight [[Kenshō#Training after kenshō|further practice]] is necessary, to deepen the insight and learn to express it in daily life.{{sfn|Sekida|1996}} In Chinese Chán and Korean Seon, this further practice consists of further pondering of the same Hua Tou.<ref group=web name="Lachs" /> In Rinzai-Zen, this further practice is undertaken by further koan-study, for which elaborate curricula exist.{{sfn|Hori|2000}}{{sfn|Hori|2005b}} In Sōtō-Zen, [[Shikantaza]] is the main practice for deepening insight.

==Varieties in koan-practice==

===Chinese Chán and Korean Seon===
{{Main|Hua Tou}}

In Chinese Chán and Korean Seon, the primary form of Koan-study is ''kanhua'', "reflection on the koan",{{sfn|Schlütter|2000|p=168}} also called [[Hua Tou]], "word head".{{sfn|Ford|2006|p=38}} In this practice, a fragment of the koan, such as "''mu''", or a "what is"-question is used by focusing on this fragment and repeating it over and over again:<ref group=web>[http://www.dharmanet.org/samples/chansample2.htm Dharmanet, ''Huatou'']</ref>{{sfn|Lachs|2012}}
{{quote|Who is it who now repeats the Buddha's name?<br>
Who is dragging this corpse about?<br>
What is this?<br>
What is it?<br>
What was the original face before my father and mother were born?<br>
Who am I?<ref group=web>[http://www.hsuyun.org/chan/en/essays/bychuanzhi/759-huatoupractice.html hsuyun.org, ''The Hua-Tou Practice'']</ref>}}

The student is assigned only one hua-tou for a lifetime.{{sfn|Ford|2006|p=38}} In contrast to the similar-sounding "who am I?" question of [[Ramana Maharshi]], hua-tou involves raising "great doubt":<ref group=web name="Lachs">[http://www.nondualitymagazine.org/nonduality_magazine.2.stuartlachs.interview.htm Nonduality Magazine (2010), ''Interview with Stuart Lachs'']</ref>
{{quote|This koan becomes a touchstone of our practice: it is a place to put our doubt, to cultivate great doubt, to allow the revelation of great faith, and to focus our great energy.{{sfn|Ford|2006|p=38}}}}

===Japanese Rinzai===
Kōan practice is particularly important among Japanese practitioners of the Rinzai sect.

====Importance of koan-study====
This importance is reflected in writings in the Rinzai-school on the koan-genre. [[Zhongfeng Mingben]]{{efn|group=note|{{lang|zh|中峰明本}}, Wade Giles: ''Chung-feng Ming-pen''; Japanese ''Chūhō Myōhon''}} (1263–1323),{{sfn|Dumoulin|2005b|p=155}} a Chinese [[Chinese Chán|Chán-master]] who lived at the beginning of the [[Yuan Dynasty]], revitalized the Rinzai-tradition,{{sfn|Dumoulin|2005b}} and put a strong emphasis on the use of koans. He saw the kung-ans as "work of literature [that] should be used as objective, universal standards to test the insight of monks who aspired to be recognized as Ch'an masters":{{sfn|Griffith Foulk|2000|p=22}}
{{quote|The koans do not represent the private opinion of a single man, but rather the hundreds and thousands of [[bodhisattva]]s of the [[Trailokya|three realms]] and [[Ten spiritual realms|ten directions]]. This principle accords with the spiritual source, tallies with the mysterious meaning, destroys birth-and-death, and transcends the passions. It cannot be understood by logic; it cannot be transmitted in words; it cannot be explained in writing; it cannot be measured by reason. It is like the poisoned drum that kills all who hear it, or like a great fire that consumes all who come near it. What is called "the special transmission of the Vulture Peak" was the transmission of this; what is called the "direct pointing of [[Bodhidharma]] at Shao-lin-ssu" is this.{{sfn|Mingben|2006|p=13}}}}

[[Musō Soseki]] (1275–1351), a Japanese contemporary of Zhongfeng Mingben, relativized the use of koans.{{sfn|Dumoulin|2005b|p=164–165}} The study of koans had become popular in Japan, due to the influence of Chinese masters such as Zhongfeng Mingben. Despite belonging to the Rinzai-school, Musō Soseki also made extensive use of ''richi'' (teaching), explaining the sutras, instead of ''kikan'' (koan). According to Musō Soseki, both are ''upaya'', "skillful means" meant to educate students.{{sfn|Dumoulin|2005b|p=164–165}} Musō Soseki called both ''shōkogyu'', "little jewels", tools to help the student to attain [[satori]].{{sfn|Dumoulin|2005b|p=164–165}}{{refn|group=note|The term ''shōkogyu'' comes from a Chinese poem in which a lady calls the attendant using the word ''xiaoyu'', Jap. ''shōkogyu'', to warn her lover.{{sfn|Dumoulin|2005b|p=165}} The poem figures in an interaction between [[Wuzi Fayan]] (1024–1104) and his student [[Yuanwu Keqin]], the teacher of [[Dahui Zonggao]]. Yüan-wu was assigned the koan "The verbal and the nonverbal are like vines clinging to a tree". Yuanwu gained [[satori]] with the phrase "She keeps calling out to [her maid] ''Xiaoyu'' although there is nothing the matter.{{sfn|Schlütter|2000|p=186}} It is only because she knows Tanlang [her lover] will hear her voice".{{sfn|Schlütter|2000|p=198 note 96}} The same koan was assigned to Dahui Zonggao.{{sfn|Schlütter|2000|p=197 note 94}}}}

====Koan curricula====
In Rinzai a gradual succession of koans is studied.{{sfn|Besserman|Steger|2011|p=148}} There are two general branches of curricula used within Rinzai, derived from the principal heirs of Rinzai: the Takuju curriculum, and the Inzan curriculum.  However, there are a number of sub-branches of these, and additional variations of curriculum often exist between individual teaching lines which can reflect the recorded experiences of a particular lineage's members.  Koan curricula are, in fact, subject to continued accretion and evolution over time, and thus are best considered living traditions of practice rather than set programs of study.

Koan practice starts with the ''shokan'', or "first barrier", usually the mu-koan or the koan "What is the sound of one hand clapping?"{{sfn|Hori|2005b|p=132}} After having attained ''kensho'', students continue their practice investigating subsequent koans.{{sfn|Yampolski|2005|p=186}} In the Takuju-school, after breakthrough students work through the ''Gateless Gate'' (Mumonkan), the ''Blue Cliff Record'' (Hekigan-roku), the ''Entangling Vines'' (Shumon Kattoshu), and the ''Collection of Wings of the Blackbird'' ({{lang|ja|鴆羽集}}, ''Chin'u shū'').{{sfn|Ford|2006|p=42}} The Inzan-school uses its own internally generated list of koans.{{sfn|Ford|2006|p=42}}

Hakuin's descendants developed a fivefold classification system:{{sfn|Besserman|Steger|2011|p=148}}
#''Hosshin'', dharma-body koans, are used to awaken the first insight into [[sunyata]].{{sfn|Besserman|Steger|2011|p=148}} They reveal the [[dharmakaya]], or Fundamental.{{sfn|Hori|2005b|p=136}} They introduce "the undifferentitated and the unconditional".{{sfn|Hori|2005b|p=136–137}}
#''Kikan'', dynamic action koans, help to understand the phenomenal world as seen from the awakened point of view;{{sfn|Besserman|Steger|2011|p=148-149}} Where ''hosshin'' koans represent ''tai'', substance, ''kikan'' koans represent ''yu'', function.{{sfn|Hori|2005b|p=137}}
#''Gonsen'', explication of word koans, aid to the understanding of the recorded sayings of the old masters.{{sfn|Besserman|Steger|2011|p=149}} They show how the Fundamental, though not depending on words, is nevertheless expressed in words, without getting stuck to words.{{sfn|Hori|2005b|p=138}}
#''Hachi Nanto'', eight "difficult to pass" koans.{{sfn|Hori|2005b|p=135}} There are various explanations for this category, one being that these koans cut off clinging to the previous attainment. They create another Great Doubt, which shatters the self attained through ''satori''.{{sfn|Hori|2005b|p=139}} It is uncertain which are exactly those eight koans.{{sfn|Hori|2003|p=23}} Hori gives various sources, which altogether give ten ''hachi nanto'' koans:{{sfn|Hori|2003|p=23-24}}
#*Miura and Sasaki:
#**Nansen's Flower (Hekigan-roku Case 40)
#**A Buffalo Passes the Window (Mumonkan Case 38)
#**Sōzan's Memorial Tower (Kattō-shō Case 140)
#**Suigan's Eyebrows (Hekigan-roku Case 8)
#**Enkan's Rhinoceros Fan (Hekigan-roku Case 91)
#*Shimano:
#**The Old Woman Burns the Hut (Kattō-shō Case 162)
#*Asahina Sōgen:
#**Goso Hōen's "Hakuun Said 'Not Yet'" (Kattō-shō Case 269)
#**Shuzan's Main Cable (Kattō-shō Case 280).
#*Akizuki:
#**Nansen Has Died (Kattō-shō Case 282)
#**Kenpō’s Three Illnesses (Kattō-shō Case 17).
#''Goi jujukin'' koans, the [[Five Ranks|Five Ranks of Tozan]] and the Ten Grave Precepts.{{sfn|Besserman|Steger|2011|p=151}}{{sfn|Hori|2005b|p=135}}

According to [[Akizuki Ryomin|Akizuki]] there was an older classification-system, in which the fifth category was ''Kojo'', "Directed upwards". This category too was meant to rid the monk of any "stink of Zen".{{sfn|Hori|2005b|p=143}} The very advanced practitioner may also receive the ''Matsugo no rokan'', "The last barrier, and ''Saigo no ikketsu'', "The final confirmation".{{sfn|Hori|2005b|p=143}} "The last barrier" when one left the training hall, for example "Sum up all of the records of Rinzai in one word!"{{sfn|Hori|2005b|p=143}} It is not meant to be solved immediately, but to be carried around in order to keep practising.{{sfn|Hori|2005b|p=143}} "the final confirmation" may be another word for the same kind of koan.{{sfn|Hori|2005b|p=143}}

====Post-satori practice====
Completing the koan-curriculum in the Rinzai-schools traditionally also led to a mastery of Chinese poetry and literary skills:
{{quote|[D]isciples today are expected to spend a dozen or more years with a master to complete a full course of training in koan commentary. Only when a master is satisfied that a disciple can comment appropriately on a wide range of old cases will he recognize the latter as a dharma heir and give him formal "proof of transmission" (J. ''[[inka shomei]]''). Thus, in reality, a lot more than ''satori'' is required for one to be recognized as a master (J. ''shike'', ''roshi'') in the Rinzai school of Zen at present. The accepted proof of ''satori'' is a set of literary and rhetorical skills that takes many years to acquire.{{sfn|Griffith Foulk|2000|p=42}}}}

After completing the koan-training, ''Gogo no shugyo'', post-satori training is necessary:{{sfn|Hori|2005b|p=145}}
{{quote|[I]t would take 10&nbsp;years to solve all the kōans [...] in the sōdō. After the student has solved all koans, he can leave the sōdō and live on his own, but he is still not considered a roshi. For this he has to complete another ten years of training, called "go-go-no-shugyō" in Japanese. Literally, this means "practice after satori/enlightenment", but [[Keido Fukushima|Fukushima]] preferred the translation "special practice". Fukushima would explain that the student builds up a "religious personality" during this decade. It is a kind of period that functions to test if the student is actually able to live in regular society and apply his koan understanding to daily life, after he has lived in an environment that can be quite surreal and detached from the lives of the rest of humanity. Usually, the student lives in small parish temple during this decade, not in a formal training monastery.<ref name=antaiji10 group=web>[http://antaiji.dogen-zen.de/eng/adult50.shtml Muho Noelke, ''Part 10: What does it take to become a full-fledged Sōtō-shu priest and is it really worth the whole deal?'']</ref>}}

====Breathing practices====
[[Hakuin Ekaku]], the 17th&nbsp;century revitalizer of the Rinzai school, taught several practices which serve to correct physical and mental imbalances arising from, among other things, incorrect or excessive koan practice.  The "soft-butter" method (''nanso no ho'') and "introspection method" (''naikan no ho'') involve cultivation of [[Qi|ki]] centered on the tanden (Chinese:[[dantian]]). These practices are described in Hakuin's works [[Orategama]] and [[Yasen Kanna]], and are still taught in some Rinzai lineages today.

===Japanese Sōtō===
Though few Sōtō practitioners concentrate on kōans during meditation, the Sōtō sect has a strong historical connection with kōans, since many kōan collections were compiled by Sōtō priests.

During the 13th&nbsp;century, [[Dōgen]], founder of the Sōtō sect in Japan, quoted 580 kōans in his teachings.{{sfn|Bodiford|1993|p=144}} He compiled some 300 kōans in the volumes known as the Greater [[Shōbōgenzō]]. Dōgen wrote of Genjokōan, which points out that everyday life experience is the fundamental kōan.

However, according to Michel Mohr,
{{quote|...kōan practice was largely expunged from the Sōtō school through the efforts of [[Gentō Sokuchū]] (1729–1807), the eleventh abbot of Entsuji, who in 1795 was nominated abbot of [[Eiheiji]]".{{sfn|Mohr|2000|p=245}}}}

===Sanbo Kyodan and White Plum Asanga===
The [[Sanbō Kyōdan|Sanbo Kyodan]] school and the [[White Plum Asanga]], which originated with the Sōtō-priest [[Hakuun Yasutani]], incorporates koan-study. The Sanbo kyodan places great emphasis on [[kensho]], initial insight into one's true nature,{{sfn|Sharf|1995c}} as a start of real practice. It follows the so-called Harada-Yasutani koan-curriculum, which is derived from [[Hakuin]]'s student Takuju. It is a shortened koan-curriculum, in which the so-called "capping phrases" are removed. The curriculum takes considerably less time to study than the Takuju-curriculum of Rinzai.{{sfn|Ford|2006|p=42–43}}

To attain kensho, most students are assigned the mu-koan. After breaking through, the student first studies twenty-two "in-house"{{sfn|Ford|2006|p=42}} koans, which are "unpublished and not for the general public",{{sfn|Ford|2006|p=42}} but are nevertheless published and commented upon.{{sfn|MacInnes|2007}}<ref group=web>[http://www.mkzc.org/foreword-to-flowing-bridge-the-miscellaneous-koans/ Ruben L. F. Habito (2007), ''Foreword to Flowing Bridge: The Miscellaneous Koans'']</ref> There-after, the students goes through the ''Gateless Gate'' (Mumonkan), the ''Blue Cliff Record'', the ''Book of Equanimity'', and the ''Record of Transmitting the Light''.{{sfn|Ford|2006|p=42}} The koan-curriculum is completed by the [[Dongshan Liangjie#Five Ranks|Five ranks of Tozan]] and the precepts.{{sfn|Sharf|1995c|p=432}}

==Classical kōan collections==
Kōans collectively form a substantial body of literature studied by Zen practitioners and scholars worldwide. Kōan collections commonly referenced in English include:
*The ''[[Blue Cliff Record]]'' (Chinese: ''Bìyán Lù''; Japanese: ''Hekiganroku''), 12th century;
*The ''[[Book of Equanimity]]'' (also known as the ''Book of Serenity''; Chinese: ''Cóngróng Lù''; Japanese: ''Shoyoroku''), 12th century;
*''[[The Gateless Gate]]'' (also known as ''The Gateless Barrier''; Chinese: ''Wúménguān''; Japanese: ''Mumonkan'') collected during the 13th&nbsp;century).
In these and subsequent collections, a terse "main case" of a kōan often accompanies prefatory remarks, poems, proverbs and other phrases, and further commentary about prior emendations.

===The Blue Cliff Record===
The ''[[Blue Cliff Record]]'' (Chinese: {{lang|zh|碧巖錄}} Bìyán Lù; Japanese: Hekiganroku) is a collection of 100 kōans compiled in 1125 by [[Yuanwu Keqin]] ({{lang|zh|圜悟克勤}} 1063–1135).

===The Book of Equanimity===
The ''[[Book of Equanimity]]'' or ''Book of Serenity'' (Chinese: {{lang|zh|從容録}} Cóngróng lù; Japanese: {{lang|ja|従容録}} Shōyōroku) is a collection of 100 Kōans by [[Hongzhi Zhengjue]] (Chinese: {{lang|zh|宏智正覺}}; Japanese: Wanshi Shōgaku) (1091–1157), compiled with commentaries by [[Wansong Xingxiu]] (1166–1246). The full title is ''The Record of the Temple of Equanimity With the Classic Odes of Venerable Tiantong Jue and the Responsive Commentary of Old Man Wansong'' {{lang|zh|萬松老評唱天童覺和尚 頌古從容庵錄}} (Wansong Laoren Pingchang Tiantong Jue Heshang Songgu Congrong An Lu) (Taisho Tripitaka Vol. 48, No. 2004)

===The Gateless Gate===
''[[The Gateless Gate]]'' (Chinese: {{lang|zh|無門關}} Wumenguan; Japanese: Mumonkan) is a collection of 48 kōans and commentaries published in 1228 by Chinese monk [[Wumen]] ({{lang|zh|無門}}) (1183–1260). The title may be more accurately rendered as ''Gateless Barrier'' or ''Gateless Checkpoint'').

Five kōans in the collection derive from the sayings and doings of [[Zhaozhou Congshen]], (transliterated as Chao-chou in Wade-Giles and pronounced Jōshū in Japanese).

===Treasury of the True Dharma Eye===
[[Dahui Zonggao]] (大慧宗杲) (1089–1163) the ''Zhengfayan zang'' (正法眼藏), "Treasury of the true dharma eye" (W-G.: Cheng-fa yen-tsang, (J.: Shōbōgenzō) a collection of koans and dialogues compiled between 1147 and 1150 by [[Dahui Zonggao]] . Dahui's 'Treasury' is composed of three scrolls prefaced by three short introductory pieces. The Zongmen liandeng huiyao 宗門聯燈會要 was compiled in 1183 by Huiweng Wuming 晦翁悟明 (n.d.), three generations after Dahui in the same line; the sermon is found in zh 20 (x 79: 173a).

Other kōan collections compiled and annotated by Sōtō priests include:
*''Treasury of the true dharma eye'' (Jap. ''Shobogenzo'' (正法眼蔵), compiled by Eihei Dogen (永平道元), 13th Century.
*''The Iron Flute'' (Japanese: ''Tetteki Tōsui'' 鐵笛倒吹, compiled by Genrō Ōryū 玄楼奥龍 in 1783)
*''Verses and Commentaries on One Hundred Old Cases of Tenchian'' (Japanese: ''Tenchian hyakusoku hyoju'', compiled by Tetsumon in 1771.)

==Examples of traditional kōans==
<!-- Note to editors: the list in this section should not attempt to interpret the meanings -->

===Does a dog have Buddha-nature===
{{Main|Mu (negative)}}

{{quote|A monk asked [[Zhaozhou Congshen|Zhàozhōu]], "Does a dog have [[Buddha nature]] or not?" Zhaozhou said, "[[Mu (negative)|Wú]]".}}

("Zhaozhou" is rendered as "Chao-chou" in [[Wade-Giles]], and pronounced "Joshu" in Japanese. "Wu" appears as "mu" in Japanese, meaning "no", "not", "nonbeing", or "without" in English. This is a fragment of Case No. 1 of the ''[[The Gateless Gate|Wúménguān]]''. However, another koan presents a longer version, in which Zhaozhou answered "yes" in response to the same question asked by a different monk: see Case No. 18 of the ''Book of Serenity''.)

===The sound of one hand===
{{quote
|text=''Two hands clap and there is a sound. What is the sound of one hand?'' ({{lang|ja|隻手声あり、その声を聞け}})
|sign=[[Hakuin Ekaku]]
}}

Victor Hori comments:
{{quote|...in the beginning a monk first thinks a kōan is an inert object upon which to focus attention; after a long period of consecutive repetition, one realizes that the kōan is also a dynamic activity, the very activity of seeking an answer to the kōan. The kōan is both the object being sought and the relentless seeking itself. In a kōan, the self sees the self not directly but under the guise of the kōan ... When one realizes ("makes real") this identity, then two hands have become one. The practitioner becomes the kōan that he or she is trying to understand. That is the sound of one hand.<ref group=web>[https://web.archive.org/web/20190424203451/http://www.thezensite.com/ZenEssays/HistoricalZen/translating_zen_phrasebook.pdf G. Victor Sogen Hori (1999), ''Translating the Zen Phrase Book''. Nanzan Bulletin 23, 1999, p. 44–58] (PDF)</ref>}}

===Original face===
{{Main|Original face}}

[[Huineng|Huìnéng]] asked [[Hui Ming]], "Without thinking of good or evil, show me your original face before your mother and father were born." (This is a fragment of case No. 23 of the ''Wumenguan''.)

===Killing the Buddha===
{{quote
|text=''If you meet the [[Gautama Buddha|Buddha]], kill him.'' ({{lang|zh|逢佛殺佛}})
|sign=[[Linji Yixuan|Linji]]
}}

===Other koans===
*A student asked Master Yun-Men (A.D. 949) "Not even a thought has arisen; is there still a sin or not?" Master replied, "[[Mount Sumeru]]!"
*A monk asked [[Dongshan Shouchu]], "What is Buddha?" Dongshan said, "Three pounds of [[flax]]." (This is a fragment of case No. 18 of the ''Wumenguan'' as well as case No. 12 of the ''[[Blue Cliff Record]]''.)
*A monk asked Zhaozhou, "What is the meaning of the ancestral teacher's (i.e., [[Bodhidharma]]'s) coming from the west?" Zhaozhou said, "The cypress tree in front of the hall." (This is a fragment of case No. 37 of the ''Wumenguan'' as well as case No. 47 of the ''Book of Serenity''.)

==See also==
;Buddhism
*[[Kirigami (Soto Zen)|Kirigami]]
*Koans mentioning [[Subhuti]], [[Tanzan]],  and [[Tetsugen]]
*[[List of koans by Yunmen Wenyan]]
*[[Mu (negative)|Mu-koan]]
*[[Original face]]
*[[Wild fox koan]]
;Christianity
* [[Apophatic theology]]
;Other
*[[Hacker koan]]s, humorous expressions of [[hacker culture]]

==Notes==
{{reflist|group=note|35em}}

==References==

===Book references===
{{reflist|25em}}

===Web references===
{{Reflist|group=web}}

==Sources==
{{refbegin|35em}}
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{{refend}}

==Further reading==
*Loori, John Daido. ''Sitting with Koans: Essential Writings on the Zen Practice of Koan Study''. Wisdom Publications, 2005. {{ISBN|978-0-86171-369-1}}
*Steven Heine, and Dale S. Wright, eds. ''The Kōan: Texts and Contexts in Zen Buddhism.'' Oxford and New York: Oxford University Press, 2000. {{ISBN|0-19-511749-2}}
*Hoffmann, Yoel.tr. ''The Sound of the One Hand.'' Basic Books, 1975. {{ISBN|978-0-465-08079-3}} This book contains examples of how some Zen practitioners '''answer''' the koans "correctly". Originally published in Japan almost a century ago as a critique of fossilization of Zen, that is formalization of koan practice.

==External links==
*[https://web.archive.org/web/20041009183526/http://www.ciolek.com/WWWVLPages/ZenPages/KoanStudy.html Zen Buddhism Koan Study Pages]
*[http://www.thezensite.com/MainPages/koan_studies.html Koan Collections and Studies]

{{Zen}}
{{Buddhism topics}}

[[Category:Kōan| ]]
[[Category:Metaphors]]
[[Category:Riddles]]
[[Category:Zen texts]]
[[Category:Spiritual practice]]