Kuji-in
The kuji-in or jiǔzìyìn, also known as Nine Hand Seals, is a system of mudras and associated mantras that consist of nine syllables. The mantras are referred to as kuji, which literally translates as nine characters. The syllables used in kuji are numerous, especially within Japanese esoteric Mikkyō.
Scholars have stated that kuji is of Taoist origin, not Buddhist. There is no mention of the kuji in any of the Buddhist Shingon or Buddhist Tendai records that Japan imported. The use of kuji is essentially a layman's practice and is uncommon in many orthodox Buddhist traditions. It is, however, found extensively in Shugendō, the ascetic mountain tradition of Japan and Ryōbu Shintō, which is the result of blending Shingon Buddhism and Shinto. The nine Buddhist cuts in order are: Rin, Pyo, To, Sha, Kai, Jin, Retsu, Zai, and Zen.
History
The kuji are first introduced in the Bàopǔzǐ, a Chinese Taoist text written by Gé Hóng c. 280–340 CE). He introduces the kuji in chapter 17, entitled Dēngshè, as a prayer to the Liùjiǎ, ancient Daoist gods. In Daoist magic, the Jiǎ are powerful celestial guardians and are among the gods of the Celestial Thunder Court of Emperor Xuanwu.The kuji are first seen in line 5 which reads,
抱朴子曰：“入名山，以甲子開除日，以五色繒各五寸，懸大石上，所求必得。又曰，入山宜知六甲秘祝。祝曰，臨兵鬭者，皆陣列前行。凡九字，常當密祝之，無所不辟。要道不煩，此之謂也。”
Translation:
The kuji form a grammatically correct sentence in Classical Chinese. They come from this section of the chapter. They are written as which can be roughly translated, " soldiers/fighters descend and arrange yourselves in front of me", or "May all those who preside over warriors be my vanguard!"
Other translations are possible, as variations exist within Japanese esoteric Buddhism. According to the Baopuzi, the kuji is a prayer to avert difficulties and baleful influences and to ensure that things proceed smoothly. To this end, it can be said that the primary purpose of kuji is abhisheka and exorcism.
The Daoist kuji are next cited in a text called The commentary on the discourse about the Sutra on Immeasurable Life, and on the verses about the vow to be reborn , also known as the Commentary on the treatise on rebirth in the Pure Land written by the Pure Land Buddhist Taluan.
How the kuji arrived in Japan is still a matter of debate. Some contemporary scholars assert that the kuji arrived in Japan via China, via Jōdo-shū and Shugendō, around the 8th century, if not later. As to what the kuji consisted of at the time it arrived in Japan is unknown. Mudras are found in Daoism as well as in Shugendō. Some have suggested that Shugendō created the mudras currently associated with the kuji, as most of the information known about the kuji comes from Shugendō literature.
Kuji's origins
The earliest known Japanese application of the kuji comes from the Shingon monk Kakuban, who was an academic of Taluan's writings and teachings. Kakuban introduced several kuji formulas dedicated to Amitābha, in his text The Illuminating Secret Commentary on the Five Chakras and the Nine Syllables.The kuji formulas Kakuban introduces are commonly grouped under the title zokushu, and are entirely unrelated to original Daoist kuji. The monk Shinran, founder of Jōdo Shinshū sect, introduced several new kuji formulas, also dedicated to Amitābha. Nichiren, founder of Nichiren Buddhism, introduced a kuji prayer derived from chapter 26 of the Lotus Sutra, where it is uttered by the god Vaiśravaṇa.
Neither Kūkai, the founder of Shingon, nor Saichō, the founder of Tendai, mentioned kuji in any of their writings. It may be assumed that they were unfamiliar with the kuji or that they considered them only part of a minor teaching. Regardless, the nine syllables of the kuji have been associated with several religious and philosophical aspects of Japanese esoteric Buddhism. They are associated with the five chakras, the five elements, specific directions of the compass, colors, and deities.
Variations on the ryōbu kuji
There are numerous variations of the nine original Taoist kuji in Japanese Buddhism. Most of these variations occurred well after the introduction of the kuji into Japan. Some, however, are other Taoist formulas taken from Taoist writings and Buddhist sutras. The kuji that is most often seen in the context of budo, or martial arts, and also in general, consists of the nine original Taoist syllables Rin Pyou Tou Sha Kai Chin Retsu Zai Zen. The fact that the Taoist kuji are not seen in Japanese documents and writings until at least the 1500s, and then not extensively until around the Edo and Meiji periods indicates that they were either not extensively practiced, or taught as kuden. However, the fact that so many koryu list the kuji in their makimono indicates it must have been considered an essential teaching. And the fact the kuji are listed in numerous kobudō makimono from the 1500s onward, is proof that the kuji were practiced by the bushi.Significance of the number nine
Why the number nine is used has also been of concern to some. The number nine is seen in Taoist divination as the perfect number for yang/yo, the “bright side” when determining the individual hexagram lines according to the I-ching. Some have suggested that the number nine refers to the nine planets, that the Taoist believe directly influence human destiny, or to the seven stars of the Big Dipper plus the two attendant/guardian stars which Taoist believe is the gateway to heaven, and which each star is a Taoist deity. The Imperial Palace had nine halls, the celestial sphere has nine divisions, both in Buddhism and Taoism, heaven is 'nine enclosures'. The nine submandalas of the Vajradhãtu-mandala correspond to the imperial city of Ch'ang-an.Kuji no in (Hand Seals of the Nine Syllables)
The Kuji-in, “Nine Hand Seals,” refers to the mudra associated with the nine syllables themselves, whereas kuji-ho refers to the entire ritual of kuji and encompasses the mudra, mantra and meditation. Kuji-kan is a specialized form of Buddhist meditation. Technically the word “Kuji no in” refers only to the hand postures, whereas “kuji no shingon” refers to the related incantations. There are hundreds of mudras in Shingon alone. Shugendō itself has hundreds of mudras, as does Taoism. Many of these mudras are shared; however, many are not. To further complicate this fact, there are also untold numbers of variations on a given mudra, and many mudras are associated with more than one deity or idea. Furthermore, a mudra may have more than one name, or one association depending on its purpose. Practitioners would be wise to keep this in mind when practicing kuji ho.Yin/Yang and kuji
The dualistic influence of inyogoku is apparent only in respects to the mudra of certain kuji rituals. As stated earlier the kuji in and of itself is a simple prayer. The obvious influences of onmyōdō is clearly seen in the mudra themselves which were added later. Especially in regard to the first and last mudras, the mudras associated with the syllables "to" and "sha", "kai" and "jin". These mudras are obvious yin and yang counterparts. This is significant in that the concept of yin and yang is seen as encompassing all the cosmic phenomena, all eternity between the two polar opposites. The mudra gejishi-in and its immediate counterpart naijishi-in clearly represent this yin/yang relation. In fact, not only do these two related mudras represent the alpha and omega by themselves, but the two lions associated with them take this association a step further. The two lions are commonly seen outside the doors of Buddhist temples, where they stand as guardians against evil and baleful influences. The first lion utters the sound “A” which symbolizes the alpha, that all reality and phenomena are, in the tradition of mikkyō, said to neither absolutely exist, nor non-exist – they arise in dependence on conditions, and cease when those conditions cease. Whereas the second lion utters the sound “Un” which symbolizes the omega, the destruction of all evils; it summarizes the two basic false views of nihilism and externalism and shows them to be false. The truth of things is that they are neither real nor unreal. This description also applies to the next two mudra, gebbaku-in and its immediate counterpart neibbaku-in. The first and last mudra, occupy the two most important positions, the beginning and the end, again with relation to the Taoist and mikkyō points of view of the alpha and omega.In relation to yin and yang theory, the yang aspect is the light, masculine, positive, offensive, absolute, horizontal, left, forward, upward. While the yin aspect is the dark, feminine, negative, defensive, relative, vertical, right, backward, down.
Ryobu kuji and the martial arts
Ku-ji ho as generally practiced in budo comes from text Sugen jinpi gyoho fuju shu or Fuju shu for short, a Shugendō document of the Tozan-ha lineage, edited between 1871 and 1934 by Nakuno Tatsue. The original compiler is unknown, but it appears to incorporate numerous Shugendō rituals from various Shingon sects such as Tachikawa-ryu. The text compilation of texts appears to span a time period from the 1200s on up to 1500s and 1600s. The Fuju shu lists 400 rituals, 26 of them kuji-ho..The two particular techniques of ku-ji that are most directly related to budo, and most widely known are kuji hon-i and kuji no daiji. These two kuji rituals are centered in the esoteric deities of Shingon mikkyo, the Shidaitenno and Godai myo-o. Other groupings of deities exist as well depending on the sect and purpose of the kuji.