Touhou Suimusou ~ Immaterial and Missing Power. , commonly abbreviated as IaMP in English speaking circles, is a versus fighting game collaboratively developed by Twilight Frontier and Team Shanghai Alice released in 2004. It is the first spinoff in the Touhou series, and it is numbered as the 7.5th installment as the game's events place between Perfect Cherry Blossom (seventh) and Imperishable Night (eighth), although it was released after Imperishable Night. After the success of Immaterial and Missing Power, the game was followed up with Scarlet Weather Rhapsody in 2008, the first of several Touhou fighting game sequels.