Theodorus Cornelus Louis Kok ( *  Friday, November 23, 1906 in The Hague; †  Friday, May 28, 1999) was a well-known Dutch chess composer of endgame studies

Chess player
Like all talented young chess players, Kok wanted to become world champion. As a passionate attacker, he knew little about the end game. His father gave him 5 guilders for Berger's standard work. But he was also inspired by the book in memory of Weenink.

Chess composition
Between 1933 and 1938 Kok composed numerous endgame studies.

In his subsequently published monograph, which partly draws on earlier articles, they are grouped thematically: self-stalemate, stair maneuvers, intersection combinations for Nowotny and Plachutta, etc. But orthodox tasks, retroanalysis and self-checkmates are also represented.

After his book was published, he published under the pseudonyms Dorus Jansen, Kees Jansen and Gerrit Jansen. His contributions to the theory of queen and rook endgames are noteworthy.

A manuscript by Kok on the subject of The Black Lady in Zugzwang was found in Selman's estate, which ARVES published posthumously 50 years later.

Private
Kok studied mathematics and physics in Leyden. After graduating during the Great Depression, he sorted and distributed eggs in his father's wholesale company. He then worked as a bookmaker and statistician. From 1942 until his retirement he was an actuary at an insurance company in Utrecht and hardly composed any studies.

Kok´s famous endgame study

Kok won with a brillant chess study (Ke3/Kg2) the first price in

Československý šach in August 1934 (598) 

   In the original publication, the solution only ends when the imprisoned black king is checkmated by the white knight. Since the white knight also has other ways to win after the black king has been imprisoned, the solution is dualistic right to the end. 

Correction

Solution 1. Nc7-a8!! A fantastic corner move! [Thematic try: 1. Nd5? h3 2. Bh2 Kh2 3. Kf2 Be6! 4. Ne3 Bd7!=]. The white knight voluntarily goes into the corner to avoid later attacks by the black bishop. 1...Bf5-d7 2. Na8-b6! h3 3. Bb8-h2! Bd7-c6! 4. Na7-c8! This prevents a stalemate later on. 4.Na7xc6? would be therefore only a draw. 4...Kg2xh2 5. Ke3-f2 1-0 ...afterthen it is an easy win. After 5.Ke3-f2 the black king is trapped and defenceless against the 2 free white knights. The study should therefore end here. The black bishop, as a defender, can no longer prevent mate. The knights then have several possibilities to reach the key positions and to check mate on Ng3#. The use of space in this study is excellent. Kok was 27 years old at the time.

Look schachstudienkomponisten.fandom.com

Literature
Theodorus Cornelis Louis Kok: Eindspelen en problems, The Hague, self-published, 1939.
Individual evidence
  Jan van Reek; Henk van Donk: Endgame study composing in The Netherlands and Flanders. Margraten, 1992, p. 41 ff ISBN 90-72939-12-3

Web link
Compositions by Theodorus Cornelis Louis Kok on the Schwalbe PDB server: 

20 chess problems can be found. 

Yet another chess problem: yacpdb.org can be found 114 chess problems: 22 chess problems and 92 endgame studies

Others: 72 endgame studies composed by Kok are selected on Dutch Website ARVES (arves.org)

Source: de.wikipedia.org, arves.org