From's Gambit Puzzle (Rated 1131): Fork — Material Gain

A fork is a tactical attack in which one piece creates threats against two or more targets at once. In this middlegame position, White’s knight is under pressure, but Black’s queen and bishop are vulnerable to a forcing response. The key idea is to use check as a tempo, placing the knight on an active square where it attacks the king while also targeting valuable material. Once the king responds, White can secure a decisive material gain.