In Kingdom Hearts what's the difference between Birth By Sleep and Keyblade Wars?

[pink_is_metal]

I searched for pictures and they seemed to have the same picture
where there this bald guy (whom I never saw in KH and KHII) with a heartless :/

 

[imported_nobody]

They're the same game. It happens I think when Sora was only 7. Cause Ven (which I think is Sora's cousin) in Birth by Sleep, saw Sora and Riku fighting each other when they were still kids.
Well that bald guy is Master Xehernort, and that's all I know...sry

 

[jonny11890]

Birth By Sleep is a game that takes place during the keyblade wars. The keyblade wars was an event that took place long before Sora was born. Difference: Keyblade wars=event while Birth By Sleep=game