KNSB FIDE
BK

Bert Koster

Rated since January 2023

RIVALRY

Nemesis
Bos, W. (Wim)
Games: 6 · Win rate: 50%
Kryptonite
Kamminga, W.R. (Rob)
Games: 9 · Win rate: 0%
Easy Target
Harmanny, W. (Wim)
Games: 5 · Win rate: 100%

The good & the bad

Best wins
WEPEREN VAN, J.J. (JOS) 1902
11827 S.C. Middelstum interne competitie 03-06-2025 t/m 04-09-2025 (020024) · Tuesday 8 July 2025
BOL, J. (JAN) 1850
11828 S.C. Middelstum interne competitie 04-06-2025 t/m 05-09-2025 (020024) · Thursday 24 July 2025
BRANDSMA, F. (FRITS) 1822
11828 S.C. Middelstum interne competitie 04-06-2025 t/m 05-09-2025 (020024) · Friday 5 September 2025
HOF, J.M. (JAN MARK) 1766
11828 S.C. Middelstum interne competitie 04-06-2025 t/m 05-09-2025 (020024) · Wednesday 30 July 2025
SCHOLTEN, E. (EVERT) 1726
11827 S.C. Middelstum interne competitie 03-06-2025 t/m 04-09-2025 (020024) · Tuesday 5 August 2025
Worst losses
PEEK, J.C. (JAN) 1310
7931 NOSBO competitie 2023-2024 November 2023 · Tuesday 31 October 2023
TOXOPÉUS, C. (CARSTEN) 1660
6984 NOSBO competitie 2022-2023 April 2023 · Tuesday 11 April 2023
BRANDSMA, F. (FRITS) 1682
5867 interne competitie SC Middelstum 2022-2023 Groep A · Tuesday 14 March 2023
HOF, J.M. (JAN MARK) 1694
5867 interne competitie SC Middelstum 2022-2023 Groep A · Tuesday 4 October 2022
MOLEWIJK, K. (KOEN) 1709
10558 NOSBO competitie 2024-2025 Februari 2025 · Tuesday 11 February 2025
Chessfestival Groningen Seniorentoernooi - Friday 26 December 2025 +0–1=3 -30.5
NOSBO-competitie 2025-2026 ronde 7 Groep A Monday 13 April 2026 +0–0=1 -5.4
NOSBO-competitie 2025-2026 ronde 6 (minus één uitgestelde wedstrijd)… Monday 16 March 2026 +1–0=0
NOSBO-competitie 2025-2026 ronde 5 (minus één uitgestelde wedstrijd)… Monday 16 February 2026 +0–1=0 -13.5
S.C. Middelstum interne competitie 03-03-2026 t/m 16-06-2026 (020024) Monday 2 February 2026 +4–2=3 +5.9
NOSBO-competitie 2025-2026 ronde 4 Groep A Monday 19 January 2026 +0–0=1 -1.5
S.C. Middelstum interne competitie 08-01-2026 t/m 26-02-2026 (020024) Thursday 1 January 2026 +2–2=1 -14.5
NOSBO-competitie 2025-2026 ronde 3 Groep A Friday 28 November 2025 +0–0=1 -4.5
NOSBO-competitie 2025-2026 ronde 2 Groep A Monday 10 November 2025 +0–1=0 -16.3
S.C. Middelstum interne competitie 07-10-2025 t/m 16-12-2025 (020024) Tuesday 9 September 2025 +3–2=3 -22.9
S.C. Middelstum interne competitie 09-09-2025 t/m 30-09-2025 (020024) Tuesday 9 September 2025 +1–0=3 +15.2
S.C. Middelstum interne competitie 04-06-2025 t/m 05-09-2025 (020024) Wednesday 4 June 2025 +8–1=4 +91.7
S.C. Middelstum interne competitie 03-06-2025 t/m 04-09-2025 (020024) Tuesday 3 June 2025 +9–1=2 +86.5
NOSBO competitie 2024-2025 Februari 2025 Wednesday 1 January 2025 +1–1=0 -14.1
NOSBO-competitie 2023-2024 April 2024 Sunday 1 October 2023 +1–0=0 +8.5
NOSBO competitie 2023-2024 November 2023 Sunday 1 October 2023 +0–1=0 -21.1
NOSBO competitie 2022-2023 April 2023 Monday 24 October 2022 +0–1=0 -4.7
interne competitie SC Middelstum 2022-2023 Groep A Tuesday 13 September 2022 +7–5=5 +32.8

Team Competition

Current team
Middelstum I
Klasse 1A · 2025-2026 · 6 games
Past teams
Middelstum I
Zestallen 1e fase A · 2024-2025
Middelstum I
Zestallen · 2023-2024
Middelstum I
Achttallen A · 2022-2023

Rating History

Loading rating history...

Peak Ratings

Classic 1934 Nov. 1, 2025
Rapid 1831 March 1, 2026
Blitz 1831 March 1, 2026

Games

Wins 37
Losses 19
Draws 27
Win Rate 45%

Performance by Color

Color Wins Draws Losses Win Rate
White 19 11 11 46%
Black 18 16 8 43%

Recent Matches

Naaijer, J. (Joop) (1558) Tuesday 2 June 2026 DRAW -8.2
Kamminga, W.R. (Rob) (2033) Tuesday 26 May 2026 LOSS -5.9
Brandsma, F. (Frits) (1895) Tuesday 12 May 2026 LOSS -10.1
Bol, J. (Jan) (1829) Tuesday 28 April 2026 WIN +12.4
Hof, J.M. (Jan Mark) (1843) Tuesday 21 April 2026 DRAW +0.4
Berg van den, H.T. (Thijmen) (1669) Tuesday 14 April 2026 DRAW -5.4
Harmanny, W. (Wim) (1581) Tuesday 7 April 2026 WIN +4.8
Melle van, J.P. (Joost) (1595) Tuesday 24 March 2026 WIN +5.1
Kleine de, R.F. (Roderick) Tuesday 17 March 2026 WIN
Bos, W. (Wim) (1588) Tuesday 10 March 2026 WIN +4.9
Brandsma, F. (Frits) (1898) Tuesday 3 March 2026 DRAW +2.3
Scholten, E. (Evert) (1723) Thursday 26 February 2026 LOSS -17.1
Welling, S.C. (Sophie) (1830) Friday 20 February 2026 LOSS -13.5
Kamminga, W.R. (Rob) (2014) Thursday 19 February 2026 LOSS -7.3
Prins, B.H. (Be) (1663) Wednesday 4 February 2026 WIN +6.2
Harmanny, W. (Wim) (1587) Thursday 29 January 2026 WIN +3.6
Spears, R. (Russell) (1849) Tuesday 20 January 2026 DRAW -1.5
Weperen van, J.J. (Jos) (1895) Wednesday 14 January 2026 DRAW +0.1
Ridder de, H.P.L. (Henk) (1764) Tuesday 30 December 2025 DRAW -5.1
Karsdorp, G.N. (Nico) (1836) Monday 29 December 2025 DRAW -2.8