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MatPlus.Net Forum Competitions A. Zarur-100 JT - Questions and answers.

### A. Zarur-100 JT - Questions and answers.

Questions from the composers and answers from the judge.

1) Does a tempo move "influence solution B" as requested in the announcement?
1) Yes, a tempo move is thematic. [the Judge]

2) Is it thematic if the thematic piece is pinned in the mating position. For example:
Scheme:
Kh1, Qh7, Sg1 (3)
Kb2, Re2, Rh8, Pd2 (4)
h#2
1.Kc1 Sh3 (Sf3?) 2.Kd1 Qb1 #
The second thematic solution with Sg1 mating, is missing in this scheme, of course.

2) The white knight is thematic, it does not affect the checkmate. [the Judge]

3) The scheme below shows the solution where the thematic piece does not mate. Can wPf3 be considered thematic?
The doubt refers to the fact that it can be removed from the board without affecting checkmate but it guards e5 in the mating position.
White: Kh5 Lh2 Pe5f3g3
Black: Kf5 Ta1 Pe4
h # 2
1.Ta6 f4 2.Te6 g4 #

3) wPf3 is thematic in this case. It can be placed on c3 and the solution will be (almost) the same, with 1…c4 by white. [the Judge]

4) Considering your answer to Question 2, I ask you if wSa5 in the following position is thematic:
White: Kd2 Lc1 Sa5
Black: Kh8 Tc8 Ld1 Ph7
h # 2
1.Lb3 Sc6 2.Lg8 Lb2 #
wSa5 moves to c6 and closes the bT’s line. In the mating position, it does not guard any flight around the bK, but if it is removed from the board, the bT avoids the mate (3.Tc3!).
The second thematic solution with Sa5 mating is missing in this scheme, of course.

June 21, 2020

if I understand well, the answer to the question 4 is : if the piece closes a black line that controls the mate it is useful and than non thematic.

now a question 5 "...The mating piece of a solution..."
in case of a battery mate, the rear piece, or the front piece are called "the mating piece" ? or possibly both of them ?

the mating piece of solution A must play no role in solution B : should it play ? or may it stay without playing ?

(4) Posted by Paz Einat [Tuesday, Jun 30, 2020 19:10]

Question 4 in the first post: as Jacques wrote - with Sa5 being thematic, the move Sc6 leaves it unthematic as removing it will result in no mate. As it turns out, if the black rook is on c6 and is captured by the knight, this will be thematic... I will go with the definition.

"...question 5 "...The mating piece of a solution..."
in case of a battery mate, the rear piece, or the front piece are called "the mating piece" ? or possibly both of them ?"
My answer is that it can be just the front piece, or just the rear piece, and it can be both. I will be flexible and willing to receive interesting ideas.

"the mating piece of solution A must play no role in solution B : should it play ? or may it stay without playing ?"
Of course it can play, but it also can stay without playing, but note that the theme definition requires it to somehow influence that solution.