I did a quick Google search and didn't find much, but I am curious why they get exclusive songs from western artist?

They don't even go on iTunes.

I'm sure it's more of an artist thing than a Japan thing.

Breaking Benjamin released a few songs exclusively in japan and they have never toured there.

Foster the People have also released exclusive songs.

Wouldn't this just encourage piracy?

Because any country that can go crazy for Metal Machine Music is Land of the Hipster Gods and so they just deserve it.

This is a pretty good answer I'd say.

Lamb of God has some sick japan exclusive songs on their japan-only albums. I can only explain it by the huge and warm welcome they always get when they go there.

Sometimes bands will play brand new versions of a song that they'll never play again when they go to a radio station.

Perhaps it's their way of saying "we aren't coming over, so take this as a consolation"?

I would bet its a decision made by the labels than the artists themselves. Probably strike deals with what ever music distribution agencies that are in japan

Because it takes longer for albums to be released there and CDs cost more money there.

Japan used to be one of the largest single music markets, but after over a decade of recession I am not so sure that is true anymore. Seems more like an old habit than anything.

This has been happening for decades, with almost any band on a major label.

It's mostly because starting in the 1970's, the labels in Japan used virgin vinyl on most pressings, (which was uncommon in other countries) and the better sound quality was in high demand by the collectors.

As time went on, and everyone was producing top quality vinyl, Japan labels needed new reasons stay popular. So they started obtaining extra songs and producing unique/rare artwork for albums. This kept the collectors buying their expensive imports.

And now it's kinda just a tradition of the industry, and another way to get your money.


edit: Oh, and it's not very common for bands to tour Japan, so that's why there were many "live in Japan" albums in the 70-90's (because it was a so special when it happened)
Another reason they had content we didn't.