This one has puzzled me quite a bit. Probably to save SqaureEnix's last remaining reputation with the Japanese audience, I don't know. Not that it really matters to most of us though.

I know, I was just wondering for a while

Because no one will buy it on 360 in Japan.  That's why.

X360 games don't generally sell well in Japan. I assume Sqaure thinks the effort wouldn't be worth the sales. After all, more people own a PS3 than X360 in Japan, so chances are the PS3 version would sell more.

Square probably thought it wouldn't be worth it.
 
Japan is pretty loyal to their own hardware companies.

" Because no one will buy it on 360 in Japan.  That's why. "

" I'd imagine because either Microsoft didn't give them enough money or Sony gave them enough money.  Probably a combination of those. "

" Because no one will buy it on 360 in Japan.  That's why. "

" Well it is going to be Multiplatform on the PS3 and 360 in North America and Europe so why will it only be on the PS3 in Japan? "

The word was they weren't developing the 360 version along side the PS3 version, so making that port requires extra development time.  Even if it's a little time, it's probably not worth holding up the Japanese release as 360 has a small installed base there.
 
If it had been made on 360 from day one as well as PS3, I think they'd still release it in Japan.

Yep as others have said, the market really isn't there. Honestly I assume most people in Japan with a 360 probably own a PS3 anyway by now.

As stated, the sales in japan are gonna soo poor in japan. plus in japan there are more ps3 units than 360 in homes.

Because the sales of the 360 version could not possibly be enough in Japan to warrant the cost of producing boxes, manuals, and pressing discs.  People in Japan just do not want 360 games.  Bayonetta on PS3 is far and away outselling the 360 version so far, and it's been well known that the game is blatantly better on the 360.

Because no one would buy it for the 360 in Japan.

" Well it is going to be Multiplatform on the PS3 and 360 in North America and Europe so why will it only be on the PS3 in Japan? "

Because their Square, and for every positive step forward they do, they have to take another step either backward or off to the side. 
 
It's simply another Square oddity. 
Like releasing a demo packaged in a re-release of film you already own and claiming downloadable demo's are exclusive to the west, or the absurdity of "will they", "will they not" make a Final Fantasy VII remake, or concluding that the reason why there are no new entries in the Chrono series is because the DS port didn't sell well, or only having one voice track on a blu-ray disk, or concluding that few months for releasing an English localized copy is something new, or claiming that Final Fantasy is a genre (personal favorite :D), or....yeah, it goes on forever.  
(Holy crap, I just did Holden Caulfield there. GO ONE SENTENCE PARAGRAPH!!!!)

It's just weird, and in some cases pretty stupid. Nothing that terrible. 
I'm still a fan, of certain teams of individuals in the giant bloated mess that is Square. 
In the case of releasing the Japanese version only on the Ps3 there, I assume the logic is to appeal to their Japanese base. Many people point to the lack of install base in regards to the Ps3 versus the 360, I can agree to that. I can also agree that getting your copy, of your game on as many platforms as possible is also a viable business practice. I can easily see sales of 360's getting a jump, similar to what happened to Vesperia. 

" im pretty sure microsoft paid them a ton of money to port it to 360 in america so they could have at least one "holy shit?!" thing to mention at e3. "

" im pretty sure microsoft paid them a ton of money to port it to 360 in america so they could have at least one "holy shit?!" thing to mention at e3. "

Sales of a 360 version would be tiny in comparison to numbers on PS3, it would most probably be a waste of money to bring it out on 360 natively.

"@L4wz said:

" Well it is going to be Multiplatform on the PS3 and 360 in North America and Europe so why will it only be on the PS3 in Japan? "

Because even if all 12 people who own a 360 in Japan buy FFXIII, they won't make any money. "

Because the 360 doesn't sell well in Japan.

" The word was they weren't developing the 360 version along side the PS3 version, so making that port requires extra development time.  Even if it's a little time, it's probably not worth holding up the Japanese release as 360 has a small installed base there.  If it had been made on 360 from day one as well as PS3, I think they'd still release it in Japan. "

Who would buy it?  Everyone who owns a 360 in Japan more than likely has a PS3...and no idiot would pick the 360 version over the PS3 version if they have a HDTV and full 5.1 speaker setup.

I think it's because there are no 360 owners in Japan and Microsoft has spent far too much money on 360 marketing over there anyway for them to try to get this on 360.

so few ps3´s in JP, and maybe some money hat.

Even if anyone ACTUALLY has a 360 in japan they would buy it on the better system.

Possibly they didn't want to have to delay the game to prepare a 360 port.

Because Xbox 360 software sales in Japan are abysmal.

they already know that in japan it will sell amazingly on ps3 so they wont need to put it on 360. while in US they have doubts so they are porting it.. thats what i think but it could also be some $ from MS

" You guys are all wrong, it's like I said Sony and SE have a contract, even though the Xbox 360 does poorly in Japan, that didn't stop all the other multiplatform games from releasing both versions there. "

" @K0rN said:

" You guys are all wrong, it's like I said Sony and SE have a contract, even though the Xbox 360 does poorly in Japan, that didn't stop all the other multiplatform games from releasing both versions there. "

Uh...there are quite a bit of multiplatform games here in Tokyo that only come out for PS3. "

Because its the right system of the two to be on.

" @TwoOneFive said:

" im pretty sure microsoft paid them a ton of money to port it to 360 in america so they could have at least one "holy shit?!" thing to mention at e3. "

I somehow doubt it had anything to do with a particular company paying them money to release/not release it on other system.  FFXIII is costing Square billions, even if it turns out to be one of the best selling games ever, they may still not make a lot of money from it.  It's multiplatorm, simply because it'll sell more copies that way.  The same reason practically everything else is multiplatform these days too. "