Mega Man Battle Network 4 is the fourth game of the Mega Man Battle Network series, released for Game Boy Advance in 2003 with two different versions: Red Sun (Tournament Red Sun in Japan) and Blue Moon (Tournament Blue Moon in Japan). In this game, Lan Hikari and MegaMan partake in a series of NetBattle tournaments. A sequel, Mega Man Battle Network 5, was released in the following year.