The Clemenz Opening is a chess opening beginning with the move: 1. h3
This opening is named after Hermann Clemenz (1846–1908), an Estonian player. Like Anderssen's Opening, 1.a3, 1.h3 is a time-wasting move, as it makes no claim on the central squares, nor does it aid development. It also leads to a slight weakening of White's kingside, albeit not as severely as Grob's Attack (1.g4) or Barnes Opening (1.f3). Since there is no need for White to make such a time-wasting first move, it is among the rarest of the 20 possible first moves. Nevertheless, IM Michael Basman has experimented with 1.h3, usually following it up with 2.g4 (transposing to the Grob), or 2.a3 followed by a quick c2–c4, a line that has been dubbed the "Creepy Crawly".
Black has a number of playable responses, the most common being 1...d5 and 1...e5, which stake out a claim for central space. Another response, 1...b6 (or even 1...b5), intends to fianchetto a bishop to pressure White's weakened pawns, and forestall a White kingside expansion with g2–g4.
One of the weaker plausible responses by Black would be 1...f5, when White can play 2.d4, transposing to a sharp line against the Dutch Defense introduced by Korchnoi. White's idea is to play 3.g4!? as a pawn sacrifice (2.g4!? is also possible), one possible continuation being 2.d4 Nf6 3.g4!? fxg4 4.hxg4 Nxg4 5.Qd3 Nf6?? (5...g6! is forced) 6.Rxh7! Rxh7 7.Qg6#.