I've come across the Japanese model of oil filter on eBay but the prices are ridiculously high for a filter, and who knows if you'll actually recieve the Japanese filter from some of those sellers. I've seen reviews on Amazon of people who ordered packs of them expecting the Japanese part number but instead got the Thai ones. For me, i'll just stick with the Thai ones. They are close enough in quality although not quite as strong from my understanding, but they look like they would flow better. Someone on the Mazda6 forums dissected both a Thai and Japanese filter and it was handy to see what's inside. Check it out
here.