The most favored technique for inducing the novice's desperate attempt“to know”were the koan，literally“the problems。”There are said to be seventeen hundred of these problems，and the anecdote books make nothing of a man's devoting seven years to the solution of one of them。They are not meant to have rational solutions。One is To conceive the clapping of one hand。“Another is”To feel the yearning for one's mother before one's own conception。“Others are，”Who is carrying one's lifeless body？“Who is it who is walking toward me？”“l things return into One；where does this last return”？Such Zen problems as these were used in China before the twelfth or thirteenth century，and Japan adopted these techniques along with the cult。On the continent，however，they did not survive。In Japan they are a most important part of training in“expert-ness。”Zen handbooks treat them with extreme seriousness。“Koan enshrine the dilem-ma of life。”A man who is pondering one，they say，reaches an impasse like“a pursued rat that has run up a blind tunnel，”he is like a man“with a ball of red-hot iron stuck in his throat，”he is“a mosquito trying to bite a lump of iron。”He is beside himself and redoubles his efforts。Finally the screen of his“observing self”between his mind and his problem falls aside；with the swiftness of a flash of lightning the two-mind and problem-come to terms。He“knows。”
The significance of the koan does not lie in the truths these seekers after truth dis-cover，which are the world-wide truths of the mystics。It lies in the way the Japanese conceive the search for truth。
The koan are called“bricks with which to knock up on the door。”“The door”is in the wall built around unenlightened human nature，which worries about whether pres-ent means are sufficient and fantasies to itself a cloud of watchful witnesses who will allot praise or blame。It is the wall of shame which is so real to all Japanese。Once the brick has battered down the door and it has fallen open，one is in free air and one throws away the brick。One does not go on solving more koan。The lesson has been learned and the Japanese dilemma of virtue has been solved。They have thrown themselves with desper-ate intensity against an impasse；for“the sake of the training”they have become as“mosquitoes biting a lump of iron。”In the end they have learned that there is no im-passe-no impasse between gimu and giri，either，or between giri and human feelings，between righteousness and giri。They have found a way out。They are free and for the first time they can fully“taste”life。They are muga。Their training in“expertness”has been successfully achieved。
Even a person who has undergone no training at all may have a sort of muga experi-ence。When a man watching Noh or Kabuki plays completely loses himself in the specta-cle，he too is said to lose his observing self。The palms of his hands become wet。He feels“the sweat of muga。”A bombing pilot approaching his goal has“the sweat of mu-ga”before he releases his bombs。“He is not doing it。”There is no observer-self left in his consciousness。An anti-aircraft gunner，lost to all the world beside，is said similarly to have“the sweat of muga”and to have eliminated the observer-self。The idea is that in all such cases people in this condition are at the top of their form。
Such concepts are eloquent testimony to the heavy burden the Japanese make out of self-watchfulness and self-surveillance。They are free and efficient，they say，when these restraints are gone。Whereas Americans identify their observer-selves with the ra-tional principle within them and pride themselves in crises on“keeping their wits about them，”the Japanese feel that a millstone has fallen from around their necks when they deliver themselves up to the ecstasy of their souls and forget the restraints self-watchful-ness imposes。As we have seen，their culture dins the need for circumspection into their souls，and the Japanese have countered by declaring that there is a more efficient plane of human consciousness where this burden falls away。
The most extreme form in which the Japanese state this tenet，at least to the ears of an Occidental，is the way they supremely approve of the man“who lives as already dead。”The literal Western translation would be“the living corpse，”and in all Occi-dental languages“the living corpse”is an expression of horror。It is the phrase by which we say that a man's self has died and left his body encumbering the earth。No vi-tal principle is left in him。The Japanese use“living as one already dead”to mean that one lives on the plane of“expertness。”It is used in common everyday exhortation。To encourage a boy who is worrying about his final examinations from middle school，a man will say，“Take them as one already dead and you will pass them easily。”To encourage someone who is undertaking an important business deal，a friend will say，“Be as one already dead。”When a man goes through a great soul crisis and cannot see his way a-head，he quite commonly emerges with the resolve to live“as one already dead。”
The philosophy which underlies muga underlies also“living as already dead。”In this state a man eliminates all self-watchfulness and thus all fear and circumspection。He becomes as the dead，who have passed beyond the necessity of taking thought about the proper course of action。The dead are no longer returning on；they are free。There-fore to say，“I will live as one already dead”means a supreme release from conflict。It means，“My energy and attention are free to pass directly to the fulfillment of my pur-pose。My observer-self with all its burden of fears is no longer between me and my goal。With it have gone the sense of tenseness and strain and the tendency toward depression that troubled my earlier strivings。Now all things are possible to me。”
In Western phraseology，the Japanese in the practice of muga and of“living as one already dead”eliminate the conscience。What they call“the observing-self，”“the in-terfering self，”is a censor judging one's acts。It points up vividly the difference between Western and Eastern psychology that when we speak of a conscienceless American we mean a man who no longer feels the sense of sin which should accompany wrongdoing，but that when a Japanese uses the equivalent phrase he means a man who is no longer tense and hindered。The American means a bad man；the Japanese means a good man，a trained man，a man able to use his abilities to the utmost。He means a man who can perform the most difficult and devoted deeds of unselfishness。The great American sanc-tion for good behavior is guilt；a man who because of a calloused conscience can no lon-ger feel this has become antisocial。The Japanese diagram the problem differently。Ac-cording to their philosophy-man in his inmost soul is good。If his impulse can be di-rectly embodied in his deed，he acts virtuously and easily。Therefore he undergoes，in“expertness，”self-training to eliminate the self-censorship of shame。Only then is his“sixth sense”free of hindrance。It is his supreme release from self-consciousness and conflict。
This Japanese philosophy of self-discipline is abracadabra only so long as it is sepa-rated from their individual life experiences in Japanese culture。We have already seen how heavily this shame which they assign to“the observing self”weighs upon the Japa-nese，but the true meaning of their philosophy in their psychic economy is still obscure without a description of Japanese child-rearing。In any culture traditional moral sanc-tions are transmitted to each new generation，not merely in words，but in all the elders'attitudes toward their children，and an outsider can hardly understand any nation's major stakes in life without studying the way children are brought up there。Japanese child-rearing makes clearer many of their national assumptions about life which we have so far described only at the adult level。