Daan was kind enough to post the main new weekly background images from the official Nintendo Japan LINE account earlier, but there are a couple more surprises. Only catch is that you'd need to understand Japanese to even get all three.
Inside the chat, instead of a keyboard, it gives you three images: one giant square promoting the Zelda site, but two smaller images of Toad: one with a paintbrush and one sticking out his tongue. Tap either of those to receive the following...
"Zelda striking a standing pose. At every glance, she's just beautiful."
"Hyaaa! Hoooo! I'm one to open the sail just before landing. I've got an original wallpaper gift for you. Just type 'breath [of the wild] toad' "
**If you enter ブレスキノピオくん into the chat with him you'll get a special bonus wallpaper. I won't spoil the surprise, but it's worth it! ♥️ –cort