If MS wants to go bankrupt they could buy out Sony just to cancel PS4.

Nothing. A strategy to try would be partnerng with an eastern company - even non-Japanese like Samsung - but it would be a tough hill to climb regardless. It's not just Sony. Nintendo's already launched the WiiU which will most likely dominate that market. Sony still has a solid following so they will come next and take those who don't want WiiU. There is nothing left for Microsoft, even if they present a very attractive offering. Halo, Fable, Forza... these don't resonate well with the Japanese market, so why buy it?

Buying Sony wouldn't make MS go bankrupt. They've got $70bn in cash and make $5bn in profit every quarter...

Anyway, your original statement it wrong because if MS did this they they would beat Sony in Japan.

Xbox needs an anime mascot like what they're doing with windows 8 n_n

Nothing. That's like asking what can Sony do to beat Nintendo in Japan. It's a lost battle, just let it go.

Have to admit, this is the right answer.

Sony and its assets are worth more than 70bn

Nothing, and seeing as the strong push they made in the initial years of this gen (blue dragon, lost odyssey, vesparia) won't be there it will probably sell even less than the 360.

Source?

Microsoft could buy a majority shareholding in Sony for $6bn

Nearly all games that get released for the 360 in Japan get advertised with little Lolis - DOesn't work either
They even made games that are nothing more than a loli festival

Forcing Japanese people to buy a console that they never wanted or needed for their beloved games in the beginning of this Gen was a complete wrong move.Especially after most of those games got ported later with a superior version to the PS3 with stuff like "We never wanted to make those games for the 360 but the money!!!"  from the developers.
They pissed them even more off with that and Next Gen they won't have even less success with that if they try it.
M$ should stay out of Japan and let every IP be on the Sony and nintendo side.They damaged the reputation of Japanese Developers enough cause they promised them "CoD Numbers" with every game when they support Microsoft over Sony.