As various games of the same genre influence each other, Touhou series is no exception. This page collects evidences of notable inspirations seen in Touhou games, as well as touhouisms appearing in other doujins, barring generic elements that have appeared since the dawn of shoot-em-ups.
Note: the tables only list earliest chronological appearance of evidences.
Influences on Touhou [ ]
Evidence
Seen in
Likely origin
Reimu character
Entire game
Sayo-chan, protagonist of KiKi KaiKai (Taito, 1986)
Evidence
Seen in
Likely origin
Player interaction mechanics
Entire game
Twinkle Star Sprites (ADK, 1996)
Evidence
Seen in
Likely origin
Grazing mechanic used for scoring
Entire game
Raiden Fighters (Seibu Kaihatsu, 1996)
Focused shot that slows down the character
Entire game
Batsugun (Toaplan, 1993), or Cybattler (Jaleco, 1993)
Boss invincible to bombs (entire time or during last attack)
Extra
True last boss of ChoRenSha 68k (Famibe no Yosshin, 1995)
Evidence
Seen in
Likely origin
Youmu's bullet-canceling sword attack
Entire game
Radiant Silvergun (Treasure, 1998)
Medicine 's extra attack (slowdown field)
Entire game
Metal Black (Taito, 1991)
Evidence
Seen in
Likely origin
Using shot power for bombing
Entire game
Metal Black (Taito, 1991) or Hellsinker. (Ruminant's Whimper, 2007)
Marisa -A "shadow" options
Entire game
Gradius (Konami, 1985)
Evidence
Seen in
Likely origin
Reimu-A's options
Entire game
Thunder Force II (Technosoft, 1988) (CLAWs), or Gradius V (Treasure/G.rev, 2004) (Rotate Multiples)
Reimu-C's speed-up ability
Entire game
Dogyuun!! (Toaplan, 1992)
Reimu-C's options
Entire game
Air Gallet (Gazelle, 1996)
Marisa-B's switchable option formations
Entire game
Battle Garegga (8ing/Raizing, 1996)
Communication gauge mechanics
Entire game
Shikigami no Shiro II (Alfa System, 2003)
Falling rocks that shoot revenge bullets
Stage 1
Stage 1 of Mushihimesama Futari (Cave, 2006)
Large red round bullets
Stage 6
Mushihimesama Futari (Cave, 2006)
Utsuho 's spell card #146
Stage 6
2nd form of the last boss from Psyvariar 2 (Success, 2003)
Utsuho's spell card #147
Stage 6
Last boss from ESP Ra.De. (Cave, 1998)
Utsuho's spell card #155
Stage 6
DeathSmiles (Cave, 2007)
Lullaby of Deserted Hell
Stage 5
[Bieito Romero ]'s and Mike Oldfield ' s The Song of the Sun (1996)