I can't believe I got roped into learning History facts to win at a Touhou fan game. (actually one of my weaknesses. am not at all interested in Historical facts)
Half of my playtime was me Alt-tabbing back and forth between the game and the search engine. I guess it's fun for fans to compare Touhou lore and Outside World dates, even if it may not suit the tastes of everyone. That's what kept me going.
In a way, it's about how the Outside World is reflected onto Gensokyo. Pretty clever use of the theme!
And then I tried the latest postjam version. The EXTRA mode is actually fun. No time for research, just what I've learned before, quick maths, and my gut feelings. That was the highlight for me!
Also for those interested there's a sukusuku.