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If you follow Touhou at all, then you might know Touhou Spell Bubble exists. Which is basically an officially Touhou Puzzle Bobble clone, made by the people behind PB, Taito. What you might not know is that Touhou's relationship with Taito runs very deep. Very deep. (Thread)
To start it all off, let's focus on Reimu herself. Supposedly, a main inspiration behind her creation, and by extension, the actual setting of the games, was based on an Taito arcade game, Kiki Kaikai, which is a shmup in which you control a shrine maiden named Sayo-chan.
You might not know what Kiki Kaikai is, and that's okay, and I can't exactly blame you there. You might know it for its SNES adaptation, Pocky & Rocky. Supposedly this series of games were a huge inspiration for ZUN to make the Touhou games at all.
ZUN's name is also derived from ZUNTATA, Taito's own sound team, but the similarities here are purely coincidental, as confirmed in an interview in Untold History of Japanese Game Developers.
In addition to all of this, ZUN actually worked at Taito for quite a while. From 1998 right up until 2007, in fact. The extent of his work there was mostly programming, but he did work on quite a couple high-profile titles, such as EXIT, Magic Pengel, and Graffiti Kingdom.
Speaking of Graffiti Kingdom, Reimu is an unlockable character in it! Doesn't she look lovely here?
Two years after he quit Taito, ZUN put out the 12th entry in the Touhou series, Undefined Fantastic Object. And holy hell is it full of Taito references.
UFO's main mechanic of catching UFOs from defeated enemies for bonuses and the like was inspired by Taito's 1978 arcade hit, Space Invaders.
In addition to this, there's an attack formation on stage 6 that mimicks the movement of the Space Invaders aliens, and quite a few of Kosaga's spell cards directly reference Taito games, particularly the Bubble Bobble games.
Going back to earlier, that's not even the first time a Touhou game made a Taito reference. There's a track in Highly Responsive to Prayers that's called "the Legend of KAGE", quite possibly a callback to Taito's 1985 arcade game of the same name.
Also going back to ZUN's career at Taito, Taito actually made the offer to ZUN to make a Touhou arcade game at one point during that time. But he turned down the offer.
...although that didn't stop him from licensing the IP to them, since Taito has made and still makes a lot of Touhou merch.
Quite possibly due to this, it's also the reason there are Touhou tracks in Groove Coaster, Taito's own answer to rhythm games. Yes, I know Touhou is now technically linked to Undertale since that also has tracks in this.
Which all comes back to Touhou Spell Bubble, the game that inspired me to make this thread. I guess ZUN finally gave Taito the go-ahead to make a full-ass game with the IP, huh?
ZUN has also said in interviews that Darius Gaiden is one of his favorite shmup games. Excellent taste he has.
