Japan pro baseball does not have a "wild card" team that gets into postseason playoffs as do the American and National Leagues, but the koryu-sen (interleague) period that got under way May 9 may be considered the Japanese version of a wild card in the sense that anything can happen.
The schedule of games matching Central League teams vs. Pacific League clubs continues through June 18 and could be a make-or-break period for some of the 12 Japanese teams.
For six weeks, the two leagues become one in an officially sponsored "season." The sponsor is Nihon Seimei (Life Insurance), and the team with the best record will win a "title" and collect some prize money.