Touhou Suimusou ~ Immaterial and Missing Power (東方萃夢想, romanized Touhou Suimusou, meaning Gathering Fantasy) is a japanese 2D versus fighting game collaboratively developed by Twilight Frontier and Team Shanghai Alice released in 2004.
It is numbered as the 7.5th installment in the Touhou Project because the events in the game take place place between Perfect Cherry Blossom (7th) and Imperishable Night (8th), although it was released after Imperishable Night.