Switch
1. Futari de！Nyanko Daisensou (PONOS)
2. Dairantou Smash Bros. SPECIAL (Nintendo)
3. Dragon Quest Builders 2: Hakaishin Shidoo to Karappo no Shima (Square-Enix)
4. Human: Fall Flat (Teyon Japan)
5. Super Mario Party (Nintendo)
6. Hollow Knight (Team Cherry)
7. OCTOPATH TRAVELER (Square-Enix)
8. Minecraft (Mojang)
9. Overcooked 2 (Team17)
10. Katamari Damacy Encore (Bandai Namco Entertainment)3DS
1. Minecraft: New Nintendo 3DS Edition (Microsoft Japan)
2. Tobidasu! Nyanko Daisensou (PONOS)
3. Mama ni Game Kakusareta! (Hap)
4. Dragon Quest III: Soshite Densetsu e… (Square-Enix)
5. Pocket Monsters Crystal (Pokémon)
6. Ice Station Z (Wobbly Tooth)
7. Tobidase Doubutsu no Mori amiibo+ (Nintendo)
8. Kirby no Suikomi Dai Sakusen (Nintendo)
9. Dragon Quest II: Akuryou no Kamigami (Square-Enix)
10. Shin Daikaitaku Jidai: Gai o Tsukurou (Arc System Works)
Together! The Battle Cats! is a port of a previous 3DS game on the Nintendo Switch so it seems the Japanese audience really likes this game for it to beat Super Smash Bros Ultimate in this weeks chart.
This is pretty surprising considering that Smash Bros only came out this month however Together! The Battle Cats! only costs 999 Yen which is around $9 USD which is probably why.