In some stories (possibly pure fanon; I'm not sure), Yukari is Rinnosuke's only supplier of fuel (from the outside world) for his kerosene-powered heater.
msh1120 said: wait, really? I thought it was a Gameboy or something
The Gameboy was the one where he thought it could "control and destroy" the world and he wanted to destroy it, but Yukari stopped him and mentioned that it was to play games and that there were others that "used 2 screens"
Because of Touhou 17.5, a game where petroleum starts coming out of the ground (if I remember correctly)
This smell! Don't tell me it's kerosene...!?D'bloossshGrabEmergency, Mr. Shopkeeper!BamWhat's wrong...?FretA strange liquid erupted out while I was at work shoveling snow!This is wonderful, Youmu! Now I can use the heater all I want!Ehh!? C-... congratulations...