A Great Attack In the Triangle Dutch by FM Dennis Monokroussos
One virtue of the so-called Triangle System or Triangle Slav is flexibility. After 1.d4 d5 2.c4 e6 3.Nc3 c6 (this is the standard move order, but other move orders are possible – the main game started with 1.c4 e6, for example) Black might head for a Semi-Slav (e.g. 4.Nf3 Nf6), or a Noteboom (4.Nf3 dxc4 5.e3 b5 etc.), or a Dutch of sorts after 4.e3 with 4…f5. (There’s also 4.e4, which leads to completely different positions after 4…dxe4 5.Nxe4 Bb4 6.Bd2 Qxd4.) In this game, Korobov met 4.e3 with 4…Nd7, again remaining flexible, and only after 5.Qc2 a6 6.Nf3 “went Dutch” with 6…f5. It worked beautifully, and he won a brilliant attacking game against a very strong opponent. The Dutch can be dangerous for White!