It should work on a Japanese 3DS no problem. If you're using a homebrew userland only exploit though, you're not going to be able to open Street Pass IIRC. You're going to need an older version that I not longer have and full CFW for it to work.
Gonna take this time to explain some stuff too. Somewhat recently, I decided to try to revisit 3DS and take a break from Switch. So, the newer version of JKSM that uses icons works fine when built with older versions of ctrulib and citro3d. Instead of giving up and only supporting saves and extra data, I used my solution from Switch on 3DS: Create a render target, render the title/system ID of the title to it and use it as an icon for titles lacking an icon. This means I can both use icons as I originally intended way back, but also support the various saves that have no icon to load. This solution worked fine a few years ago when I implemented it. Fast forward to now, with the latest ctrulib and citro3d and it crashes when trying to copy and compress the texture data to cache it. So, I switched over to using VRAM as I originally should have and using DMA requests only to run into the same problem eventually. I'm kind of at a loss. I was really happy I had google drive working on 3DS only for this to get in the way. Never say never, but I'm not sure if or what I'm going to do now.
JKSM on 3DS is extremely special to me. I had been sitting on it for months. I'm a hobbyist and never thought I was particularly good at programming. JKSM didn't even have a name at first. It was literally called "3DS Save Thing." To this day it still doesn't register that something I wrote was used by thousands of people all over the world at one time. Just gonna say thanks everyone who used and still do use it. Maybe it'll be a somewhat quick rewrite project someday. Time flies.
