Iuri Akobia
1.p Upal's Problemist 20 (winStudyes), 2013

White must to sacrifice pawn e6 because impossible fight against Pg2 and at the same time protect it . It is necessary to chose a correct square for the sacrifice. Here are two possible choices - e6 or e7.
[Thematic (Logical) try 1.c5? and "study in the study", BTM and draws: 1...Kh2! (1...Rh8? 2.Re7 Rh6 3.d4! Rg6 4.Re8 Kh2 5.Rh8+ Kg3 6.e7 g1Q 7.e8Q+- ) 2.Rg8 Rxe6+ 3.Kf3 g1N+! 4.Rxg1 Kxg1 5.d4 Rc6 (*Compare this position with the main line B: 6...Rc7) 6.c3 (Also, the Black has a draw after - 6.Ke4 Kf2 7.c4 Kg3! 8.Kd5 Rc8 9.c6 Kf4 10.Kd6 Rd8+ 11.Kc5 Rc8 12.Kb6 Rb8+ 13.Kc7 Ra8 14.d5 Ke5 15.Kb7 Ra4= ; or also - 6.c4 Kh2! 7.Ke4 Kg3 8.Kd5 Rc8 similar draw) 6...Rc7! zz with WTM.(compare with the main line after 7.c3!! zz); Similar thematic try 1.Kd2? Kh2 2.Rg8 Rxe6 3.c5 Rf6! 4.Ke2 Re6+ 5.Kf3 g1N+! etc; 1.d4? Kh2! (1...Kh1? 2.Rg8+- ) 2.Rg8 Rxe6+ 3.Kf3 Rf6+= ] 1...Rh7! [1...Kh2 2.Rg8 Re6+ 3.Kf3 Rxe7 4.Rxg2++- ] 2.c5! [2.d4? Kh2! (2...Kh1? 3.Rg8 Rxe7+ 4.Kd3 (f3)+-) 3.Rg8 Rxe7+ 4.Kf3 Rf7+! (not 4...g1N+? 5.Rxg1 Kxg1 6.c5! and main thematic lines) 5.Ke4 Re7+ (Rf2)=] 2...Kh2 3.Rg8 Rxe7+ 4.Kf3! [4.Kf2? Rf7+ 5.Ke3 Rf8= ] 4...g1N+! 5.Rxg1 [5.Kg4? Ne2 6.Rc8 (6.Rd8 Kg2= ) 6...Kg2= ] 5...Kxg1 6.d4! main B 6...Rc7 (*Compare with the thematic try after: 6...Rc6) [main A 6...Rd7 7.Ke4 Rc7 8.c4! (Thematic try 8.c3? Kf2 9.Kd5 Ke3 (Ra7) 10.c6 Ra7 (Ke3) 11.Kd6 Ra3 12.c7 Rxc3 ) 8...Kf2 9.d5 Rxc5 10.Kd4 Ra5 (Compare with thematic try 7.c4? in main line B: 10.Ra5) 11.d6 (Thematic try 11.c5? Ra4+ 12.Kc3 Ra1! 13.c6 Rc1+ 14.Kb4 (14.Kd2 Rc5 (c4)=) 14...Ke3= ) 11...Ra1 12.c5 Rd1+ 13.Ke5 (13.Ke4? Kg3 14.Ke5 Kf3 15.c6 loss of time) 13...Ke3 14.c6+- ] 7.c3!! zz with BTM owning to the move 1.e7! [Thematic try 7.c4? Kh2! (7...Kf1? 8.Ke3 Kg2 9.d5 Rxc5 10.Kd4 similar of main A) 8.Ke4 Kg3 9.d5 Rxc5 10.Kd4 Ra5 (c8)= (Compare with main A: 10.Ra5)] 7...Rc8 [or 7...Kh2 8.Kf4 Kh3 9.Ke5 Kg4 10.Kd6 Ra7 11.c6+- ; or 7...Kf1 8.c4 Ke1 9.Ke3 Re7+ 10.Kd3 Rc7 11.d5! Rxc5 12.Kd4+- ] 8.Ke4 Kf2 9.Kd5 Ke3 10.c6 Kd3 11.Kc5 Ke4 [or 11...Kxc3 12.d5 Rh8 13.c7+- (13.d6? Rh5+ 14.Kb6 Rd5 15.c7 Rxd6+ 16.Kc5 Rd4= ) ] 12.Kd6! [Thematic try 12.d5? Kf5! (12...Ke5? 13.c4! zz with BTM 13...Kf6 14.Kb6+- ) 13.c4 Ke5 zz with WTM 14.d6 Ke6 15.c7 Kd7= ] 12...Kd3 13.Kd7 [13.d5? Kc4!= ] 13...Ra8 14.c7 Kxc3 15.d5 Kc4 16.Kc6 Rc8 17.d6+- . Logical study with "chose of a square for sacrifice of a pawn". It should be noted that the way to zz starts with the first move! Also here is a s changes of TT and main line...