This is part of: Geography of music games.
In the arts of Japan, games and music seem to be intrinsically connected. It's the land of karaoke and rhythm game craze. Both field have a connection to video games but their influence is visible in non-electronic games. Many active independent publishers present at events like the famous Tokyo Game Market.
Some older activities have been mentioned in our article on traditional music games.
People
Game publishers with sound products
Gentosha. http://www.gentosha.co.jp/
Nebuta Beat (Rassera Game), Waratte-ha ikenai ondoku.
With many titles, some with world-wide traction (Animal Shogi, Love Letter).
Gomi Kokusai. https://gomikokusai.booth.pm/
Cowlien
Many tropes of party games covered.
Jelly Jelly Games. https://jelly2games.com/
Rhythm Party.
Publishing in addition to board game café network.
Joyable. https://joyjoyjoy.booth.pm/
Champagne Party Night, and its expansion.
Not many titles on the market.
Kakugari Shoten. https://kakugari.games/
Rirekaeism, Livehouse Yeah Yeah.
First a book publisher, with a growing list of games now.
Kokopelli Gamez. https://kokopelligamez.com/
Kimidagakki
Probably not active anymore.
Megane Itachi. http://www.youtube.com/@meganeitachi1727
From Piglet
No official site; a small operation.
Momizi Crepe. https://momizicrepe.booth.pm/
Un! Tan! Poi!
A seemingly small-hobbyist collective.
Oink Games. https://oinkgames.com
FiveLines (reimplemented as Hey Yo!).
Big not only in Japan (Scout et al).
Pentasulfide Studio. https://www.youtube.com/@ペンタススタジオ
Comical Mission
No official site; their logo drops "l" from the name.
Spiqa Design. https://spiqa.design/
Tokyo Tokkyo Kyokyakyoku, Popotan's What is it?.
This company does not specialize in games. A broad design portfolio.
Xaquinel. https://www.xaquinel.com/
Karu Uta and variants.
Many versions of Karu Uta are made for specific J-pop performers.