あの日地球にダンジョンが出現した = THAT DAY DUNGEONS APPEARED ON EARTH
あの ひ ちきゅう に だんじょん が しゅつげん した
est. Rough estimate based on volume count, reprints and magazine — not an official figure
External databases: MADB
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections