Just threaten Mate

Chess is probably the most subtle game of strategy in the world. Beginners often just attack the King from move one come hell or high water until they realize there are principles like controlling the center, developing your pieces, King safety, coordination that the world class players understand almost perfectly.

 The current world champion Magnus Carlson probably understands the principle of coordination better than any player in the history of the Royal Game. Mick Bighamian of Houston and Mack Novosad of Austin,TX were also exceptional in this facet of the game.



Despite all subtleties of chess, sometimes a caveman approach is enough to win depending on the nature of the position. In the following position, black is "up the exchange" with White to move. Black, rather greedily in this case, grabbed a rook in the corner at a1 with his Bishop. It turns out  that left him fatally weak along the a3-f8 diagonal.

See if you can find the move that forces Black to resign due to the unguardably weak e7 and f8 dark squares.