Sega and EA have entered into a deal which will see the Japanese publisher act as the main distributor for EA's titles in their native country.
The first game to be part of the deal is Suda51's Shadows of the Damned. That's due to release in Japan on the 22nd of September. Following this, Sega will publish some of EA's back-catalogue.
Such a deal isn't uncommon throughout the world. Square Enix has distributed some of Activision's titles in Japan, while THQ just signed a deal to distribute Codemasters titles in North America.