The joint study project of Momoyama Gakuin University titled "The Establishment and Development of Masked Comedy in Japan and in Italy during the Medieval and Early Modern Period and its Contemporary Practice" has been developing a series of researches and discussions on the roots of masked comedy through comparative study of Kyogen and Commedia dell'Arte. Both Kyogen and Commedia dell'Arte have long histories through which they have developed into the sophisticated styles as we know them today. On the other hand, their original spirit and dynamism has been lost or diminished. Our inquiry into the primitive forms of Kyogen and Commedia dell'Arte will hopefully contribute to restoring this spirit and dynamism to the contemporary theater. Kyogen in general is a genre of comic play whose main characters are Tarokaja , a quick-witted servant, and his master. In this point the parallelism of Kyogen and Commedia dell'Arte is often mentioned. But our interest regards another aspect of Kyogen in Nogaku : Sanbaso in Shikisanban. There are many mysterious sides to Sanbaso, probably because it maintains older elements than other Kyogen repertories. Sanbaso consists of dance rather than the form of a play and is composed of two parts : Momino-dan (stamping segment) in which the kyogen actor dances and sings rhythmically without amask; Suzu-no-dan (bell segment) in which he puts on the Kokushikijo (black old man) mask and dances solemnly with a bell tree in one hand. It is generally considered that Momi-no-dan is a dance of a young man cultivating the land and Suzu-no-dan is that of an elder sowing or planting the crop. We suggest a different interpretation. The black mask may imply a woman rather than a suntanned peasant as is generally conceived. In fact, traditional forms of Sanbaso in some regions include dances with female masks. It is evident that Shikisanban has its origin in old shamanic rituals. Shamans are often women, a mystic existence with the ability of giving birth to new lives. In the course of time the shamanic role of Sanbaso may have been taken from women and given to men who need some initiation in order to go into a trance. Momi-no-dan might be this initiation and Suzu-no-dan might be a dance of a transgender shaman. And for him a mask is necessary to turn into `something else'. It is noticed that Sanbaso derives also from the festivals of Matarajin. Matarajin is a guardian deity of Amida Buddha and of the performing arts and has many other aspects such as Kojin, Dosojin and Marebito. The worship of this deity is a mysticism and its festivals held by secret societies were very carnivalesque. The Hatsukayasai festival of Motsu-ji temple is a relic of Matarajin worship. The Ennen-no-mai performed at the end of this festival is a dance with a black old woman mask very similar to the Kokushikijo mask. Like Kyogen Commedia dell'Arte derives from old rituals and festivities, especially carnival, mystery plays and Renaissance theatrical arts. In Venice in the first half of the 16th century, the place and time of the birth of Commedia dell'Arte, a kind of performing art called momaria was greatly in fashion. In momaria there were a number of symbolic elements of pagan tradition which were also common to carnival festivities and mystery plays. Above all the presence of buffoonish characters is notable. The most important character of Commedia dell'Arte is Arlecchino, a typical buffone (fool). It goes without saying that the fool once had a shamanic role. Moreover, Arlecchino is thought to have his origin in a chthonian spirit which once had been a pagan deity (Dionisus, Hermes, Odin, etc.) and transformed into a demonic existence in the Christian era. He even has a hermaphrodite aspect. In fact, every attribute of Arlecchino, from the black mask and the slapstick to the acrobatic movements, is much more significant than is seen on the surface. Thus, we find many similarities between the black old man in Sanbaso and Arlecchino in Commedia dell'Arte. At the base of these performances lie people's awe and prayers toward nature, which has almost been forgotten in modern society.