Calculation: long lines is lesson 1 of 9 in Real-game tactics 10: Grandmaster calculation, a tactics course suited to players rated around 2400 (advanced players). Forcing sequences of four moves or more. Picture the board after every move. It has 7 interactive exercises: 7 calculated lines from real positions. You play every move on a board and get feedback straight away. The lesson is free.
What you practise
White to move and win. (4 positions)
White to move: mate in 4.
Black to move and win. (2 positions)
Worked examples
White to move and win. 1.Rgb7+ Kc8 2.Ba6 Rg2+ 3.Kf4 Nd5+ 4.Ke5 Re2+ 5.Bxe2. The invasion on the 7th rank decided it. You win the rook on e2 and come out 5 points ahead.
White to move and win. 1.Qxd5 Rxb6 2.Ra8+ Kg7 3.Qe5+ Rf6 4.Qe8 Qxa8 5.Qxa8. Every move in the line was forcing. You come out 4 points ahead in material.
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