Rule changes and competitive balance in Japanese professional baseball

Does "competitive balance" in professional baseball improve with a change in the rules for allocating new players? Using data from Japan's two professional baseball leagues, we investigate how the change from an open-bidding regime to a player draft regime affected competitive balance between 1958 and 1993. We find evidence that the change to the player draft in 1965 increased competitive balance over time in both leagues and within seasons for one of the two leagues. Our results are similar to those previously found using North American Major League Baseball data.