Calculation: long lines is lesson 1 of 9 in Real-game tactics 8: Deep combinations, a tactics course suited to players rated around 2000 (strong club 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)
Black to move and win. (3 positions)
Worked examples
White to move and win. 1.Nf6+ Kg7 2.Nh5+ Kg8 3.Qf6 Qd4 4.Rxd4. Moving the knight opened the line for the queen on h4. You come out 6 points ahead in material.
White to move and win. 1.Re8+ Kg7 2.Qf3 Rh8 3.Ne6+ Qxe6 4.Rxe6. The knight sacrifice on e6 dragged the queen away from its duty. You come out 6 points ahead in material.
chessGM