Onsens are hot spring locations hidden throughout Denshattack!'s domed Japan. Find them all for the Sento Master achievement.
Onsens (温泉) are Japan's famous hot spring baths — a cultural institution found across the country. In Denshattack!'s dystopian setting, onsens exist as hidden retreats tucked away from the domed city infrastructure, representing moments of calm within the chaotic underground world.
Unlike toolboxes or gears which are found mid-run, onsens appear to be discoverable locations — the achievement says "Experience your first Onsen" and "Visit all Onsens", suggesting you enter or interact with them rather than just collecting them at speed.
Given the game's real Japanese regional structure, onsens are likely tied to specific prefectures famous for their hot springs — Beppu (Kyushu), Hakone (Kanto), and Noboribetsu (Hokkaido) are the most famous onsen destinations in Japan.
Locations being discovered post-launch.
Community mapping at reddit.com/r/denshattack
Check back — this section updates as players find them.