| 20 jun 2026 | Thorfinnsson, Bjorn 2343 | Hjartarson, Johann 2467 | ½-½ | A29 Apertura Inglesa: King's English Variation, Four Knights Variation, Fianchetto Line, with Nb6 | Green Diamond - Final Four | 77 | Ver |
| 20 jun 2026 | Hjartarson, Johann 2467 | Thorfinnsson, Bjorn 2343 | 0-1 | A36 Apertura Inglesa: Symmetrical Variation, Ultra-Symmetrical Variation | Green Diamond - Final Four | 47 | Ver |
| 20 jun 2026 | Thorfinnsson, Bjorn 2343 | Hjartarson, Johann 2467 | 0-1 | A48 Ataque Torre: Fianchetto Defense | Green Diamond - Final Four | 53 | Ver |
| 20 jun 2026 | Heimisson, Hilmir Freyr 2428 | Hjartarson, Johann 2424 | ½-½ | A05 Ataque Indio de Rey: Spassky Variation | Green Diamond Invitational 2026 | 81 | Ver |
| 20 jun 2026 | Hjartarson, Johann 2424 | Olafsson, Helgi 2404 | 1-0 | B92 Defensa Siciliana: Najdorf Variation, Opocensky Variation | Green Diamond Invitational 2026 | 44 | Ver |
| 20 jun 2026 | Thorfinnsson, Bragi 2283 | Hjartarson, Johann 2424 | 0-1 | E97 Defensa India de Rey: Orthodox Variation, Bayonet Attack | Green Diamond Invitational 2026 | 41 | Ver |
| 20 jun 2026 | Hjartarson, Johann 2424 | Stefansson, Hannes 2445 | 1-0 | B42 Defensa Siciliana: Kan Variation, Polugaevsky Variation | Green Diamond Invitational 2026 | 25 | Ver |
| 20 jun 2026 | Hjartarson, Johann 2424 | Thorfinnsson, Bjorn 2396 | 0-1 | C55 Apertura Italiana: Two Knights Defense, Modern Bishop's Opening | Green Diamond Invitational 2026 | 24 | Ver |
| 20 jun 2026 | Ulfarsson, Magnus Orn 2313 | Hjartarson, Johann 2424 | 0-1 | B02 Defensa Alekhine: Normal Variation | Green Diamond Invitational 2026 | 42 | Ver |
| 19 jun 2026 | Hjartarson, Johann 2467 | Stefansson, Vignir Vatnar 2540 | 0-1 | B29 Defensa Siciliana: Nimzowitsch Variation, Advance Variation | Green Diamond - Final Four | 39 | Ver |
| 19 jun 2026 | Stefansson, Vignir Vatnar 2540 | Hjartarson, Johann 2467 | 1-0 | E15 Defensa India de Dama: Fianchetto Variation, Nimzowitsch Variation | Green Diamond - Final Four | 35 | Ver |
| 19 jun 2026 | Gretarsson, Helgi Ass 2412 | Hjartarson, Johann 2424 | 1-0 | E95 Defensa India de Rey: Orthodox Variation | Green Diamond Invitational 2026 | 29 | Ver |
| 19 jun 2026 | Stefansson, Vignir Vatnar 2610 | Hjartarson, Johann 2424 | 1-0 | E11 Defensa Bogoindia: Vitolins Variation | Green Diamond Invitational 2026 | 25 | Ver |
| 10 jun 2026 | Mannion, Stephen R 2220 | Hjartarson, Johann 2467 | 0-1 | B09 Defensa Pirc: Austrian Attack, Weiss Variation | European Senior Chess Championship 2026 | 50+ | 36 | Ver |
| 9 jun 2026 | Hjartarson, Johann 2467 | Danielsen, Henrik 2466 | 0-1 | E17 Defensa India de Dama: Anti-Queen's Indian System | European Senior Chess Championship 2026 | 50+ | 56 | Ver |
| 7 jun 2026 | Hjartarson, Johann 2467 | Berend, Fred 2208 | 1-0 | B48 Defensa Siciliana: Taimanov Variation, Bastrikov Variation, English Attack | European Senior Chess Championship 2026 | 50+ | 29 | Ver |
| 6 jun 2026 | Sielecki, Christof 2385 | Hjartarson, Johann 2467 | ½-½ | E97 Defensa India de Rey: Orthodox Variation, Aronin-Taimanov Defense | European Senior Chess Championship 2026 | 50+ | 18 | Ver |
| 5 jun 2026 | Hjartarson, Johann 2467 | Rahal Vives, Michael Anthony 2298 | 1-0 | A40 Kangaroo Defense | European Senior Chess Championship 2026 | 50+ | 47 | Ver |
| 4 jun 2026 | Di Fonzo, Valerio 2083 | Hjartarson, Johann 2467 | 0-1 | B40 Defensa Siciliana: French Variation | European Senior Chess Championship 2026 | 50+ | 50 | Ver |
| 3 jun 2026 | Hjartarson, Johann 2467 | Mantovani, Renzo 2187 | ½-½ | A36 Apertura Inglesa: Symmetrical Variation, Ultra-Symmetrical Variation | European Senior Chess Championship 2026 | 50+ | 49 | Ver |