Here's the list, which eschews games like Fable and Assassin's Creed in favour of some games with a more... Japanese fare.
Idolmaster Idolmaster Live 4 U Viva Pinata Need for Speed: Most Wanted Perfect Dark Zero Bullet Witch Fight Night: Round 3 Rainbow Six: Vegas
Each of those games will go for ¥2000 (USD$21), which might be a challenge for Microsoft, since you can find some of those games used for under ¥1000 (USD$10). Then again, others will be bargains!
As with everywhere else, Games on Demand will launch in Japan on August 11.