A problem of clothing is how stripes of a sporting shirt could be seen when players wearing the shirt move round rapidly in a game. Here it was studied that what kind of pattern of stripe could be easy to recognize visually during rapid movement and that what conditions could affect on the visual recognition, using an experimental model which could rotate laterally a drum put on a two-tone-coloured paper with vertical stripes.
　Results were as follows:
　1. The increase in the velocity of drums showed that at first "optical illusion" (a tail of the stripes) was made wavering and it run away (I), then the stripes became to difficult to be recognized visually (II) and finally fusion of colours of the stripes was observed (III). These three findings were very clearly distinguished.
　2. The clear state of fusion of the two colours was considered to be similar to CFF (critical fusion frequency) of flickering of light spot.
　3. The stronger the retinal illumination of colour was and also the widely the view range was, the easier the stripes were recognized visually even in the relatively higher velocity of drum rotation.

DESCENTE SPORTS SCIENCE Vol.8/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE