Abstract
The purpose of this study is to examine the development of play itself through elucidation of the mode of being and the transformation of play, based on play theory by K. Nishimura and H-G. Gadamer. The fundamental sense of playing is the medial one ; the basic structure of "play" is the movement backward and forward. In addition, "play" contains elements of self-presentation. Starting from concepts of "play" like these, the mode of being and transformation of "play" are examined through observing children's play episodes. The results suggest that the transformation of "play" itself is not single-track way used commonly in the sense of the word "development". It is necessary to reconstruct a developmental theory on "play" itself based on the appreciation of the mode of being of "play".
