Is Gintama episode 21 filler?
Canon No, episode 21 of Gintama is canon.
#21
If You're A Man, Try The Swordfish! If You Go To Sleep With The Fan On You'll Get A Stomachache, So Be Careful
男ならとりあえずカジキ 扇風機つけっぱなしで寝るとおなか壊しちゃうから気をつけて
Aired 22 Aug 2006
Canon No, episode 21 of Gintama is canon.
#21
If You're A Man, Try The Swordfish! If You Go To Sleep With The Fan On You'll Get A Stomachache, So Be Careful
男ならとりあえずカジキ 扇風機つけっぱなしで寝るとおなか壊しちゃうから気をつけて
Aired 22 Aug 2006