JK

Jan Koolstra

Rated since January 2023

1596 Classic
1585 Rapid
1600 Blitz

RIVALRY

Nemesis
Looman, J.F.M. (Hans)
Games: 6 · Win rate: 50%
Kryptonite
Koolstra, J. (Jacques)
Games: 6 · Win rate: 0%
Easy Target
Kraay, J. (Jos)
Games: 6 · Win rate: 100%

The good & the bad

Best wins
VELLEKOOP, A. (ALFRED) 1735
11208 S.V. EsPion interne competitie 31-03-2025 t/m 28-04-2025 (080015) · Monday 31 March 2025
KOK, P. (PIETER) 1702
8654 EsPion interne competitie 2023-2024 Voorjaar ronde 2-5 · Monday 11 March 2024
MANK, A.H.C. (AD) 1666
8654 EsPion interne competitie 2023-2024 Voorjaar ronde 2-5 · Monday 26 February 2024
KIPS, D. (DAVID) 1658
11675 S.V. EsPion interne competitie 30-06-2025 t/m 21-07-2025 (080015) · Monday 7 July 2025
TJONG-AKIET, R. (RAF) 1644
6637 EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 1 - 3 · Monday 6 February 2023
Worst losses
HILLEBRAND, J.B.N.M. (JOS) 1348
8119 EsPion interne competitie 2023-2024 Ronde 9 - 11 · Monday 4 December 2023
SCHALEKAMP, R. (ROB) 1442
6271 EsPion Interne competitie 2022-2023 Najaar 2022 ronde 10-13 · Monday 19 December 2022
PLANTFEBER, H.J. (HENK) 1468
6784 EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 4 - 7 · Monday 27 February 2023
MERKUL, E. (EUGEN) 1476
8309 EsPion interne competitie 2023-2024 Ronde 12 - 14 · Monday 15 January 2024
SIEWERTSEN, K. (KLAAS) 1503
13647 SGA Competitie 2025-2026 Viertallen ronde 6 en 7 · Monday 30 March 2026
No FIDE-rated tournaments found.
S.V. EsPion interne competitie 31-03-2026 t/m 20-04-2026 (080015) Monday 2 February 2026 +1–0=1 +11.8
S.V. EsPion interne competitie 02-03-2026 t/m 23-03-2026 (080015) Monday 2 February 2026 +2–4=0 -13.7
S.V. EsPion interne competitie 02-02-2026 t/m 23-02-2026 (080015) Monday 2 February 2026 +1–2=0 -8.3
SGA Competitie 2025-2026 Viertallen ronde 6 en 7 Wednesday 1 October 2025 +0–1=0 -16.1
S.V. EsPion interne competitie 05-01-2026 t/m 26-01-2026 (080015) Monday 22 September 2025 +1–1=0 -7.9
S.V. EsPion interne competitie 01-12-2025 t/m 22-12-2025 (080015) Monday 22 September 2025 +1–0=1 +6.5
S.V. EsPion interne competitie 03-11-2025 t/m 24-11-2025 (080015) Monday 22 September 2025 +0–1=2 -7.9
S.V. EsPion interne competitie 29-09-2025 t/m 27-10-2025 (080015) Monday 22 September 2025 +1–2=0 +0.1
S.V. EsPion interne competitie 22-09-2025 t/m 22-09-2025 (080015) Monday 22 September 2025 +0–0=1 +6.6
S.V. EsPion interne competitie 28-07-2025 t/m 25-08-2025 (080015) Monday 2 June 2025 +1–6=0 -47.2
S.V. EsPion interne competitie 30-06-2025 t/m 21-07-2025 (080015) Monday 2 June 2025 +3–2=0 +3.7
S.V. EsPion interne competitie 02-06-2025 t/m 23-06-2025 (080015) Monday 2 June 2025 +4–1=1 +11.2
S.V. EsPion interne competitie 12-05-2025 t/m 26-05-2025 (080015) Monday 3 February 2025 +1–1=1 +4.2
S.V. EsPion interne competitie 31-03-2025 t/m 28-04-2025 (080015) Monday 3 February 2025 +1–2=0 +5.8
S.V. EsPion interne competitie 03-03-2025 t/m 24-03-2025 (080015) Monday 3 February 2025 +1–1=0 -1.0
S.V. EsPion interne competitie 03-02-2025 t/m 24-02-2025 (080015) Monday 3 February 2025 +1–2=1 +2.0
S.V. EsPion interne competitie 27-01-2025 t/m 27-01-2025 (080015) Monday 23 September 2024 +1–0=0 +9.6
S.V. EsPion interne competitie 06-01-2025 t/m 20-01-2025 (080015) Monday 23 September 2024 +1–1=0 -2.7
S.V. EsPion interne competitie 28-10-2024 t/m 23-12-2024 (080015) Monday 23 September 2024 +2–4=3 -23.2
S.V. EsPion interne competitie 23-09-2024 t/m 21-10-2024 (080015) Monday 23 September 2024 +0–2=1 -11.4
EsPion interne competitie 2023-2024 Voorjaar ronde 15-17 Monday 2 October 2023 +1–0=1 +9.7
EsPion interne competitie 2023-2024 Voorjaar ronde 11-14 Monday 2 October 2023 +1–1=1 -10.6
EsPion interne competitie 2023-2024 Voorjaar ronde 6-10 Monday 2 October 2023 +0–2=1 -15.8
EsPion interne competitie 2023-2024 Voorjaar ronde 2-5 Monday 2 October 2023 +2–2=0 +21.9
EsPion interne competitie 2023-2024 Ronde 15 - 17 Monday 2 October 2023 +1–1=0 -8.1
EsPion interne competitie 2023-2024 Ronde 12 - 14 Monday 2 October 2023 +1–2=0 -17.6
EsPion interne competitie 2023-2024 Ronde 9 - 11 Monday 2 October 2023 +1–1=1 -16.2
EsPion interne competitie 2023-2024 Ronde 5-8 Monday 2 October 2023 +1–1=0 +4.6
EsPion interne competitie 2023-2024 Ronde 1-4 Monday 2 October 2023 +1–1=0 +0.2
SGA Competitie 2022-2023 3e Klasse B ronde 3 Saturday 1 October 2022 +0–1=0
EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 17 Monday 26 September 2022 +0–0=1 +4.8
EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 13 - 16 Monday 26 September 2022 +2–2=0 +13.2
EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 8 - 12 Monday 26 September 2022 +0–1=2 +4.7
EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 4 - 7 Monday 26 September 2022 +2–1=1 +10.2
EsPion Interne competitie 2022-2023 Voorjaar 2023 ronde 1 - 3 Monday 26 September 2022 +1–1=0 +18.1
EsPion Interne competitie 2022-2023 Najaar 2022 Ronde 14-16 Monday 26 September 2022 +2–1=0 +8.4
EsPion Interne competitie 2022-2023 Najaar 2022 ronde 10-13 Monday 26 September 2022 +2–2=0 -10.1

Rating History

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Peak Ratings

Classic 1650 April 1, 2024
Rapid 1632 Aug. 1, 2025
Blitz 1607 March 1, 2026

Games

Wins 41
Losses 53
Draws 20
Win Rate 36%

Performance by Color

Color Wins Draws Losses Win Rate
White 18 10 27 33%
Black 23 10 26 39%

Recent Matches

Bezemer, C. (Casper) (1551) Monday 20 April 2026 DRAW -1.7
Stokman, L.N. (Lennart) (1628) Monday 13 April 2026 WIN +13.5
Siewertsen, K. (Klaas) (1503) Monday 30 March 2026 LOSS -16.1
Koopman, G.J.K. (Gabriella) (1451) Monday 23 March 2026 WIN +7.3
Koopman, G.J.K. (Gabriella) (1451) Monday 23 March 2026 WIN +7.3
Koolstra, J. (Jacques) (1618) Monday 16 March 2026 LOSS -12.1
Koolstra, J. (Jacques) (1618) Monday 16 March 2026 LOSS -12.1
Dekker, C.C. (Casper) (2005) Monday 9 March 2026 LOSS -2.1
Dekker, C.C. (Casper) (2005) Monday 9 March 2026 LOSS -2.1
Wastiaux, R. (Roland) (1845) Monday 23 February 2026 LOSS -5.3
didac.peris Monday 16 February 2026 WIN
Velden van, R. (Rudolf) (1947) Monday 2 February 2026 LOSS -3.1
Calcar van, B.T. (Bas) (1225) Monday 19 January 2026 WIN +2.1
Mank, A.H.C. (Ad) (1697) Monday 12 January 2026 LOSS -10.0
Kerkhoff, F.C. (Frans) (1710) Monday 22 December 2025 DRAW +3.2
Jay, M.B. (Michael) (1296) Monday 15 December 2025 WIN +3.3
Golovinskii, A.G. (Aleksandr) Monday 24 November 2025 DRAW
Wieringa, E.A. (Ric) (1788) Monday 10 November 2025 DRAW +5.4
Vaassen, M. (Mick) (1601) Monday 3 November 2025 LOSS -13.3
Wastiaux, R. (Roland) (1810) Monday 27 October 2025 LOSS -6.4