Play to the square initially occupied by the King

By Abdelzaiz Onkoud

StrateGems N°78 , January-March 2016

Play to the square initially occupied by the King is a very elegant idea. The idea is also conducive to combinations with well-known themes and ideas. Summarizing with a few simple examples will not do justice here. There are so many examples that this idea has developed a variety of shapes which deserve to be shown.

• Type 1 – Play of the black piece to the square initially occupied by the black King
• Type 2 - Play of the white piece to the square initially occupied by the black King
• Type 3 - Play of the white piece to the square initially occupied by the white King
• Type 4 - Play of the black piece to the square initially occupied by the white King
• Type 5 – (Type 1 + Type 2)
• Type 6 – (Type 1 + Type 3)
• Type 7 – (Type 1 + Type 4)
• Type 8 – (Type 2 + Type 3)
• Type 9 – (Type 2 + Type 4)
• Type 10 – (Type 3 + Type 4)

Below are examples for each group. The first eight diagrams have been published before while the last two diagrams are originals. [Editor‟s note to the judges: Please consider the last two examples for the Informal Tourney for 2016.]

King versus Rooks

By Abdelaziz Onkoud

StrateGems  N° 70 , April- June 2015

[Editor’s note. A recent group of helpmate problems, featuring King vs. Rooks, by the renowned Moroccan composer, Abdelaziz Onkoud, prompted me to ask Abdelaziz to describe this interesting condition with examples. I have dubbed this condition The Onkoud Theme.] Definition: Two Rooks are captured by opposing Kings after the line between them is closed by the pieces of the same or opposing colors.

A - Predecessors Before going any further, I would like to show you six problems which feature the King vs. Rooks mechanism . A few weeks later we composed a double Rundlauf of the White King using the same (King vs. Rooks) mechanism (See diagram II). Afterward, I concentrated on composing problems by using the full extend of this mechanism.

B - The birth of the King vs. Rooks mechanism In October 2014, Mike Prcic emailed me a h#4 with one solutions. It had a black Bishop rundlauf. He asked me to look for possible improvements. A day later I found a second solutions and introduced a mechanism based on the capture of two black Rooks by the white King, after closing the lines between black Rooks by two different black pieces on the same square g4 (See diagram I).

C – The definition of the King vs. Rooks mechanism Two Rooks of the same color are captured by the opposing King after the line between them is closed:

• - by the pieces of the same color (Forms I and VI)
• - by the pieces of opposite color (Forms II and VII)
• - by the pieces of both colors (Forms III and VIII)
• - by the same piece (Forms IV, V, IX and X)

Here are the different forms of the mechanism

• Form I: A closing of black Rooks’ lines by two black pieces.
• Form II: A closing of black Rooks’ lines by two white pieces.
• Form III: A closing of black Rooks’ lines by one black and one white piece.
• Form IV: A closing of black Rooks’ lines by the same black piece.
• Form V: A closing of black Rooks’ lines by the same white piece.
• Form VII: A closing of white Rooks’ lines by two black pieces.
• Form VIII: A closing of white Rooks’ lines by one white and one black piece.
• Form IX: A closing of white Rooks’ lines by the same white piece.
• Form X: A closing of white Rooks’ lines by the same black piece.

Recurrence of the 2 nd move by the black King on the 1 st move in h#2

By Abdelaziz Onkoud

StrateGems N°83 , July September 2018

Let's consider the following idea in a 2-solution helpmate in two moves: The 2 nd move by k in one solution reappears on the 1 st move of the second solution.

We are going to study the reasons preventing Black or White from copying the same play on the 1 st moves, in the solution where the k plays on B2. 1.X A 2.k(a) 1.k(a) ... 2.... The inversion may fail in two different ways:

1.k(a) ... 2.X?? (X does not work, because the k prevents X or A which is not possible, or A prevents X.)

1.k(a) A?? 2... (A does not work, because X is not possible or A is not possible or A attacks the k or A prevents X.)

Here are some of the reasons:

• 1- Because some white Pawns are blocked (A is not possible)
• 2- Because White will check the k (X does not work because A prevents X and A attacks the k.)
• 3- Because the lines of white pieces are closed (A is not possible)
• 4- Because White captures black units that are necessary for the solution (A prevents X)
• 5- Because the k closes the lines of black pieces (X does not work, because the k prevents X)
• 6- Because the white pieces need sacrifices of black pieces (A is not possible)
• 7- Because the white pieces must be unpinned (A is not possible).

At the Marianka festival in August 2016, the tourney theme required that black moves played on B1 in one solution be repeated on B2 in another solution, according to the following scheme: Idea scheme: 1..... 2.a ... 1..... 2.b ... 1.a 2...... 1.b 2...... I already had N°2 in stock and also an article in the planning stage.

It was an opportunity for me to compose examples with the different, above-mentioned, reasons. I was especially interested in the motives concerning the black King. I excluded the black move inversions (as per rules of the Marianka tourney). If it was allowed, the idea would lose its interest in my opinion. New moves were needed.

My thanks to Michel Caillaud for the perspective presented as I was finishing the article and to Eric Huber for his translation