Headed to Japan in 2 weeks.

I was wondering if anyone had any experience shopping in Japan for nice denim or a great jacket but for big boys. I'm usually a 40 in waist size for US sizes and wear a 42 in Iron Heart denim. Will I even be able to find anything in my size? I have all of these great stores lined up to visit but on all of their websites, pants rarely go above 38. Even the "customize your own jeans" shop I made an appt with messaged me asking if I wanted to cancel since the jeans I asked about weren't available in my sizes.

Any experience as a big back shopping for dope clothes out there? There's only so much heartache I can take lol.