| 1585.9 | 916.2 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1391.9 | 838.2 | 2022 South Africa Junior Blitz Chess Championships (U14) | 2 | 2022-12-05 | B | B | 1 | 0.68 | 0.32 | 1.2 | 0.55 | 0.45 | 9 |
| 1386.6 | 800.6 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1347.8 | 661 | Bojanala Fields Rapid-Blitz-Blindfold Champions 2022 (Rapid A) | 6 | 2022-05-28 | R | B | 0 | 0.5 | -0.5 | -3.9 | 0.62 | -0.62 | -12.4 |
| 1386.6 | 800.6 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1347.8 | 661 | Bojanala Fields Rapid-Blitz-Blindfold Champions 2022 (Blitz A) | 5 | 2022-05-28 | B | W | 1 | 0.59 | 0.41 | 1.5 | 0.7 | 0.3 | 6 |
| 1346.7 | 1338.6 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1258.1 | 1253.3 | Winter Games Chess Championships 2022 (U13 Open) | 4 | 2022-04-30 | S | W | 1 | 0.64 | 0.36 | 6 | 0.64 | 0.36 | 7.2 |
| 1376.2 | 1372.4 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1208 | 1195.3 | Bojanala SAJCC Trials - Session 1 of 3 2021 (C) | 5 | 2021-11-06 | S | W | 0 | 0.74 | -0.74 | -12.4 | 0.75 | -0.75 | -15 |
| 1390.5 | 1390.1 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1213.7 | 1200.7 | Spring at The King`s Gate 2021 (B) | 2 | 2021-09-11 | S | B | 0 | 0.66 | -0.66 | -11 | 0.68 | -0.68 | -13.6 |
| 1352.7 | 1342.3 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1189.9 | 1182.8 | Lebone II 2020 (U12) | 5 | 2020-02-15 | S | B | 1 | 0.65 | 0.35 | 5.8 | 0.64 | 0.36 | 7.2 |
| 1154.2 | 1147.6 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 1018.8 | 994.4 | Laerskool Proteapark 2019 (B) | 5 | 2019-05-18 | S | W | 1 | 0.7 | 0.3 | 5 | 0.72 | 0.28 | 5.6 |
| 890.2 | 890.2 | 20 | 20 | Marx, HB (Heinrich) | | NBR | 661 | 661 | Laerskool Vastrap 2018 (U10) | 2 | 2018-02-03 | S | W | 1 | 0.81 | 0.19 | 3.2 | 0.81 | 0.19 | 3.8 |
| 0 | 0 | 20 | 20 | Marx, H (Heinrich) | | NBR | 517 | 517 | Mountain Cambridge School Chess 2016 (U8) | 3 | 2016-09-10 | S | B | 1 | 0.51 | 0.49 | 8.1 | 0.49 | 0.51 | 10.2 |
