Section A1 – Win
1.Kc5 !
{Threatens both 2.Kc6 with checkmate on the spot and 2.Kb6 with a
winning position.}
( 1.Kd5 ? Kd7 2.Nf3 Bf4 ! 3.Ne5+ Bxe5 4.Kxe5 h4 = )
( 1.Kb5 ? Kb7 = )
( 1.Nf3 ? Bf4 ! 2.Kd5 Kd7 {see 1.Kd5?} )
1…Kb7
( 1…Bf4 2.Kc6 ! Bxh2
( 2…Bxd6 3.Kxd6 +- )
3.d7# )
( 1…Kd7 2.Kb6 +- )
2.Kd5 !
{The idea of this triangulation is that Black can no longer reply with
Kd7.}
( 2.Nf3 ? Be3+ 3.Kd5 Bb6 ! = {as White cannot prevent Black from
sacrificing his bishop for the two pawns.} )
2…h4
( 2…Be3 3.Ke6 Bb6 4.Kd7 +- )
3.Ng4 !
( 3.Nf3 ? {Again incorrect!} 3…h3 ! 4.Ke6
( 4.Nxg5 h2 5.Ke6 h1=Q {and here White must find a precise move
order to just draw:} 6.c8=Q+ Kxc8 7.d7+ Kc7 8.Ke7 = )
4…Kc8 5.Nxg5
( 5.Nd4 h2 6.Nc6 h1=Q 7.Na7+ Kb7 8.c8=Q+ Kxa7 9.Qc5+ Ka6 10.Qxg5
Qc6 ! = )
5…h2 6.Nf7
( 6.Ke7 h1=Q 7.d7+ Kxc7 8.d8=Q+ Kb7 = )
6…h1=Q 7.d7+ Kxc7 8.d8=Q+ {Here, White can chase the king a lot, but
the black monarch eventually escapes.} 8…Kb7 9.Nd6+ Ka6 10.Qc8+ Kb6
!
( 10…Ka5 ? 11.Qc5+ Ka4 12.Qb5+ Ka3 13.Nc4+ Ka2 14.Qb2# )
11.Qb8+ Kc5 12.Qb5+ Kd4 13.Qc4+
( 13.Nf5+ Kc3 = )
13…Ke3 14.Nf5+ Kd2 15.Qd4+ Kc2 = )
( 3.Ke6 Kc8 4.Ng4
( 4.Nf3 ? h3 5.Nxg5 {leads us back to the last sideline} )
4…h3 5.Kd5
( 5.Ne5 h2 {is a draw line we also had above} )
5…Kb7 6.Ke5 Kc8 7.Ke6 {is the main line but with a waste of time} )
3…h3
( 3…Bd2 4.Ke6 Ba5 5.Kd7 +- )
4.Ke5 !
( 4.Ke6 Kc8 5.Kd5
( 5.Ne5 ? h2 = {see above} )
5…Kb7 {Waste of time} )
4…Kc8
( 4…Bd2 5.Ke6 Kc8 {is the same position as in the main line.} )
5.Ke6 Bd2 !
{Addressing both possible replies White would have after the two other
candidate moves with the bishop.}
( 5…Bh4 6.Ne3 ! h2 7.Nd5 h1=Q 8.d7+ Kb7 9.c8=Q+ {followed by
checkmate} )
( 5…Bf4 6.Ke7 Bg5+ 7.Ke8 +- )
6.Nf6 !
{Interrupting the diagonal h4-d8 und thus shielding the king from a
bishop check on g5.}
( 6.Ne5 ? Ba5 ! = )
( 6.Ke7 ? Bb4 ! = )
6…gxf6
{Black has no other choice than to accept the sacrifice as otherwise
the knight would reach any of the key squares d5 or e8.}
7.d7+ Kxc7 8.Ke7 Bb4+ 9.Ke8 1-0