Award of 4th TT Chess Composition Microweb
C 1.3.2000

1.Kg4! zz
1...Rb5, Rc5 2.Qe6#, Se5#
1...Bc5, Bb4 2.Qe4#, Se3#
1...f2, g2 2.Qe2#, Sf2#

This problem was submitted in two versions. In original version orgue pipes that are well known, in improved version mutual interferences and withdrawals of Q, R, B. Play is schematical, but I appreciate strict geometry of board - queen's flank owing to playing black pieces, king's flank to white ones. Together 6 thematical mates.

1.Rh5 Qg5 2.Ke5 Rd5#

1.Ba2 Qb3 2.Kc4 Bd5#

Nice helpmate with good diagonal-orthogonal analogy and mates with arguable thematicity (see below), this time by two different pieces. But motivation isn't so surprising as in following helpmates.

a) 1.Qa4 Bb4+ 2.axb4 Kd5#
(1.Q~? Kd5+ 2.Kb4!), (1.Q~? Bb4+ 2.?)

b) 1.Qe4 Rd5+ 2.exd5 Kb4#
(1.Q~? Kb4+ 2.Kd5!), (1.Q~? Rd5+ 2.?)

Very good motivation in helpmate: 1st black move unpins white king (!) and prepares capture in 2nd black move by patrolling, 1st white move blocks b4/d5 but checks and thus black must parry it by capture. Finally thematical mate is from unintended set: in the announcement I meant the mates given by moving other piece than that directly checking - but I decided that present mates fulfill theme too.

1...Ka7,b5 2.Sdxb6# A, Scb6# B

1.Bf7! zz
1...Ka7,b5 2.Scxb6# B, Sdb6# A

Simple but clear motivation for reciprocal change: 1...Ka7 allows mate by patrolled knight, 1...b6 by unpatrolled. Key exchanges functions of knights and thus also mates. Very economical mutate, partly counterexmaple to my opinion that Patrol chess doesn't allow simple artistical positions.

Set Play:
1...Rd6 b 2.Rxg4# A
1...Bd6 c 2.R4xf5# B

1.Sb6! threatens 2.Rd5#
1...Be1 a 2.R4xf5# B
1...Bd6 c 2.CAxd6# C

1.Sc7! threatens 2.Rd5#
1...Se1 a 2.Rxg4# A
1...Rd6 b 2.CAxd6# C

In set play there is Grimshaw, keys have similar motivation - they free d5, unpatrol Rf4 and close black lines. Defence Be1 defends by patrolling b4, but neutralizes unpatrolling of f4, other two defences defend apparently by closing d5-d7, what is very fine patrol motivation (after 2.Rd5+? Kc4!), but allow mate on d6. But in fact, in 1.Sb6! phase knight patrols d7 again and thus there is other defence motive of Bd6 - patrolling of b4, what destroys unity. Also the basic mechanism with Grimshaw for pseudo-carousel change is well known from Brabec's orthodox works, it is only extended to Patrol chess. Thus scoring well for complexity of Patrol chess play, but less for originality.

(My originally a bit unprecise comment was corrected after Reto's claim. Sorry!)

1.Rb8 Qf3 2.Kf2 LIf8# (3.Rxf8?, Q~?)

1.Qa7 Qd3 2.Ke2 LIa6# (3.Qxa6?, R~?)

1st black move leaves threat from f8-f3/a6-d3 lines and prepares hurdle fow white lion. 1st white move removes guard from f2/e2 (what is not seen at the first sight) and sets the first mating piece. Then black moves into mating net. At last thematical mate with additional elements of white quality follows: white patrols queen by lion over piece that cannot leave f8-f3/a6-d3 due to pin that twice uses these lines in question. Original idea and excellent construction.

1.Qh1! th. 2.Qh7#
1...Sd6 2.Ra3# (Rc2, Qe1?)
1...Sxf4 2.Rc2# (Qe1, Ra3?)
1...Gg7 2.Qe1# (Ra3, Rc2?)
(1...Gd1, Se3 2.dxe4#, fxe3#)

Trial avoidance: any move of Sd5, Se4 and Ge4 remove threat from pc3: withdrawal of one piece, other two are sudennly pinned. White only needs to patrol pc3, but here it is - he mustn't unpin these pinned pieces. Very natural cycle. Many pieces only blocking of unsuitable moves, but without any doubts the most original problem in competition.