I made a shot in the dark guess Onimusha, and looking at GameFAQs, I am right.
The game on the right isn't an Onimusha game, it's Kengo 3.
Wait.. so they aren't all Kengo? Kengo 1, 2, and 3?
The first two games are Onimusha, the last is Kengo 3. As you can see, the third game doesn't have the same title as the other two. It has three kanji characters rather than two, and they're not the same kanji characters either. Similar cover design, though, so I can see the confusion.
Oh crap! I really screwed up! I know NOTHING about Imports, Playstation 2, or Japanese letters. Thank you for your help!
Okay now he is telling me it's not onimusha? I'm real confused.
Ryudo is mistaken. They are as I said. Heh, so much confusion over something so simple. Just look up "Onimusha" and "Kengo" on GameFAQs, click the "Images" tab for all of the PS2 results, and you can match up the games that way. It's an easy way to confirm.
鬼武者 = Onimusha
鬼武者2 = Onimusha 2
剣豪3 = Kengo 3.