That's because it IS a touhou arrange? (don't remember exactly the source atm, but it is, hence the name 4 chord TOUHOU)Besides, wouldn't it be more obvious since the site/game also has many other touhou arranges in it :V
I never knew that the site had many Touhou arranges. :wat:.
On a related note: things that Touhou themes sound like. Some of these are kind of a stretch, but some of these are also astonishingly similar.