The Central League announced on Sunday that all 6 teams in the league were participating in an event called The Great Central (グレートセントラル) that will be held across 6 days in August (8/17 - 8/19 and 8/24 - 8/26). As part of the event, each team will also be wearing retro uniforms from key periods in each of the team's histories.
For example, the Tigers will be wearing retro uniforms from the late 1940's when the team was called the Osaka Tigers and their uniforms were black; the Giants will be wearing retro uniforms dating back to when the Central League got it's start in 1950; and the Swallows will be wearing retro uniforms from the 1990s when they won their fourth league title.
At the end of The Great Central, all uniforms used during the 6 days will be auctioned off. Proceeds will go towards foot and mouth relief efforts in Miyazaki.