Brazil's round 9 opponents at the Chess Olympiad: how Greece and Bolivia play

Short answer

In round 9 of the 46th Chess Olympiad, on 25 September 2026, Brazil face Greece in the open section on board 10, and Bolivia in the women's event on board 30. Drawing from 514 over-the-board classical games broadcast on Lichess over the last three years, this dossier details the chess opening repertoire of both squads, the theoretical variations where opponents score below their customary levels, the phases of play where the engine detects technical inaccuracies, and the complementary indicators provided by online records. Every statistical return is accompanied by its underlying sample size, providing an essential measure of statistical reliability.

Event: 46th FIDE Chess Olympiad

How this was compiled: Checked on 24 September 2026, with round 8 finished and round 9 still to be played: it starts on 25 September at 3 pm Samarkand time (10:00 UTC). The pairings were checked on chess-results, and the individual Olympiad scores come from the same site's team rosters. The official PGN with the line-ups only appears when the round starts, so this dossier covers both opponents' full squads rather than the four boards. The repertoire uses the 514 over-the-board classical games from the last three years broadcast on Lichess, matched to each player by FIDE ID: 304 from the Greek squad and 210 from the Bolivian one. The error profile measures each player's 12 most recent games with Stockfish 19 at depth 16. Every move quoted in the text was re-measured at depth 24, with a dedicated search and a cleared hash, and endgames with up to seven pieces were checked against the Lichess tablebase. The blitz and rapid repertoire comes from verified Chess.com accounts over a 90-day window; correspondence games are excluded.

The essentials in a few lines

• In round 9, on 25 September 2026, Brazil meet Greece in the open section (board 10) and Bolivia in the women's event (board 30). In the open tournament, the Greeks hold theoretical favouritism as the 19th seeds against Brazil's 31st, supported by a 61-point rating advantage and 21.5 game points to Brazil's 19.5. In the women's event, Brazil maintain a 152-point edge in average rating. Because official board orders are confirmed only upon the release of the round's starting PGN, this dossier evaluates all ten squad members.
• Dimitrios Mastrovasilis has compiled 17 wins, 20 draws, and zero defeats across 37 games conducting the White pieces in the database. With Black, his tactical profile shifts noticeably: against 1.e4 he employs 1...e5 in 14 of 19 games, drawing 11, while in the Slav Defence his score drops to 16.7% over 3 games.
• Nikolas Theodorou, the Greek top board, emerges as the most precise player in the match under engine scrutiny, conceding an average of merely 4 centipawns per move in the endgame. Handling the Black pieces, he relies on the Petroff Defence, a chess opening in which he has recorded 30.0% over 5 games.
• Four of the five Bolivian players initiate their opening moves with 1.d4, and three (Nicole Mollo Figueroa, Daniela Cordero, and Gloria Luz Yepez Montenegro) confront 1.e4 with the French Defence. Playing Black, Yepez recorded a modest 14.3% in 7 games in the Queen's Gambit Declined and 20.0% in 5 against the Advance French.
• In round 4 against Canada, Jessica Molina succumbed to severe time pressure (zeitnot) in a balanced position, losing to Oksana Golubeva in 31 moves: with 41 seconds remaining on her clock, 31.Qh5 blundered mate in one to 31...Qxd1#.

The round 9 picture

Brazil enter round 9 enjoying strong competitive momentum. In the open tournament, round 8 concluded with a commanding 4-0 sweep over Japan, featuring Luis Paulo Supi's outstanding return of 6 points from 7 games on top board. In the women's event, a 2-2 draw with Chile brought the team to 9 match points and 20 game points, led by Juliana Sayumi Terao's 6.5 from 8. In the open standings, Brazil and Greece are level on 12 match points, with the Greeks maintaining an advantage in game points: 21.5 to 19.5.

The two encounters present markedly distinct competitive profiles. In the open section, Greece enter as the 19th seeds against Brazil's 31st. The Greek squad features five grandmasters rated between 2525 and 2633, averaging 2585 against Brazil's 2524. The Greeks have conceded two match defeats, falling to the Netherlands (1-3) and Azerbaijan (0.5-3.5), before overcoming Moldova 3-1 in round 8. In the women's section, Brazil are seeded 44th and Bolivia 73rd, with average ratings of 2137 against 1985. The Bolivian team secured a 2-2 draw against Canada in round 4, suffered narrow 1.5-2.5 defeats to Finland and Montenegro, and arrive following a 3-1 victory over Trinidad and Tobago.

The table below details the sample volume examined for each player, an indispensable metric for assessing the statistical resilience of each percentage. The Greek delegation accounts for 304 games in the database and the Bolivian squad for 210. Stamatis Kourkoulos-Arditis and Dimitrios Mastrovasilis contribute the most extensive individual samples, with 79 and 75 games respectively, drawn substantially from the Greek Team Championship. The smallest dataset belongs to Jessica Molina, with 26 games. Importantly, none of the ten competitors falls below the 10-game threshold where the dossier applies a low-confidence classification.

At the Olympiad, the standout performer for Greece has been Dimitris Alexakis, with 5.5 points from 6 games. Nikolas Theodorou and Stamatis Kourkoulos-Arditis have each registered 4.5 from 7, Dimitrios Mastrovasilis holds 4 from 7 (with losses to Jorden van Foreest and Aydin Suleymanli), and Ioannis Papaioannou has collected 3 from 5, having lost to Rauf Mamedov in round 7. For Bolivia, Nicole Mollo Figueroa paces the squad with 5 points from 7 games, representing a 2195 tournament performance. Jessica Molina and Jhoana Velarde Alarcon have each posted 4 points, while Daniela Cordero and Gloria Luz Yepez Montenegro have contributed 3 points apiece.

Greece: five grandmasters and Mastrovasilis's undefeated record with White

Among the Greek starters, Dimitrios Mastrovasilis presents the most clearly defined statistical profile. With White, he has amassed 17 wins, 20 draws, and zero losses in 37 games, yielding a formidable 73.0% scoring rate. He opens 1.e4 in 28 of those games and 1.Nf3 in 6. Against the Sicilian Defence, his return is notably more constrained than his overall average: 58.3% across 12 games with 10 draws, mirroring the identical 58.3% over 6 games following 2.Nf3 d6. Against 1...e5, he achieved 68.8% in 8 games. In practice, the Sicilian has not defeated him, but it has proven the most effective defensive system in curbing his winning ambitions. With Black, his profile changes substantially: 52.6% over 38 games. Facing 1.e4, he answers 1...e5 in 14 of 19 encounters and draws 11; against 1.d4 d5 2.c4, he selects the Queen's Gambit Declined (58.3% in 6) or the Slav Defence, where he scored 16.7% in 3 games. While a 3-game sample remains modest, it represents the primary discernible target in his Black chess opening repertoire.

Stamatis Kourkoulos-Arditis boasts the highest game count in the Greek sample (79 games) and maintains commanding numbers with both colours: 72.1% with White and 62.5% with Black. With White, 1.e4 has delivered a 75.0% return over 26 games, escalating to an impressive 90.0% across 10 encounters after 1...e5 2.Nf3 Nc6. His scoring dips when deviating into flank openings: with 1.c4, he achieves 44.4% in 9 games. Conducting Black against 1.e4, he recorded 58.3% in 18 games, encountering his most modest return in 1...e5 2.Nf3 Nc6 at 50.0% over 8 games. Against the Sicilian with 2.Nf3 d6, he managed 33.3% across 3 games, a sample too small to warrant programmatic conclusions.

Ioannis Papaioannou demonstrates the most disciplined classical repertoire with White. He initiated with 1.d4 in 14 of 18 games, scoring 82.1% without defeat. With Black, his returns are noticeably more fragile: against 1.e4 he scores 42.9% across 7 games, deploying the Sicilian with 2...d6 in 5 instances (50.0%) and 1...e5 in the remaining two, which yielded a draw and a defeat. Against 1.Nf3, he registered 5 draws in 6 games. As the Greek grandmaster with the smallest database representation (35 games), each specific subset must be interpreted with analytical caution.

Dimitris Alexakis, the Greek squad's in-form competitor in Samarkand, initiated with 1.e4 in all 31 White games in the sample, scoring 69.4%. Against the Sicilian Defence he proves exceptionally potent (79.4% in 17), with his relative vulnerability emerging in open game structures: 50.0% over 9 games against 1...e5, and 50.0% in 7 games after 2.Nf3 Nc6. With Black, he meets 1.e4 exclusively with the Sicilian across all 15 encounters (60.0%), primarily via 2...Nc6; against the Rossolimo Variation with 3.Bb5 g6 4.Bxc6, he held 50.0% in 5 games. Facing 1.d4 Nf6 2.c4 e6, his return settled at 37.5% over 4 games.

Nikolas Theodorou commands the top board with balanced consistency: 53.6% with White and 48.1% with Black against peer grandmaster opposition. With White, he employs 1.d4 in 21 of 28 games (57.1%) and 1.Nf3 in 6 (41.7%). With Black against 1.e4, he scored 46.9% in 16 games, which contains the squad's most actionable target: in the Petroff Defence, 1.e4 e5 2.Nf3 Nf6, he managed 30.0% over 5 games (one win, one draw, and three losses). Against the Sicilian he stands at 50.0% in 8 games, while against 1.d4 he displays resolute solidity, recording 58.3% across 6 games with five draws.

Bolivia: 1.d4 predominance with White and the French Defence with Black

With Black, Brazilian preparation can focus almost exclusively against 1.d4. Mollo opened with the d-pawn in 23 of 25 games, Yepez in all 30, Cordero in 16 of 17, and Molina in 10 of 12. With White, tactical preparation hinges on identifying the specific responses that trouble each opponent. Mollo scored 93.8% across 8 games against 1...d5 2.c4, and 62.5% in 8 against 1...Nf6 2.c4 e6, dropping to 37.5% in 4 games when choosing 3.Nf3. Yepez maintains 50.0% in 8 games in the Queen's Gambit Declined with 3.Nc3. Cordero recorded 25.0% over 4 games against the 1.d4 Nf6 2.Nf3 e6 3.e3 b6 setup, failing to register a win.

With White against the three Bolivians who employ the French Defence, competitive efficacy varies markedly. Nicole Mollo Figueroa demonstrates the firmest grasp of the chess opening, scoring 72.7% across 11 games after 1.e4 e6 2.d4 d5. Daniela Cordero managed 50.0% in 9 games, while Gloria Luz Yepez Montenegro fell to 40.0% over 15 encounters, with six wins, nine losses, and no draws. Against Yepez, the Advance Variation with 3.e5 yielded White 4 victories in 5 games. Against 1.d4 her difficulties deepen: 22.2% in 9 games without a victory, and 14.3% in 7 when transitioning into the Queen's Gambit Declined via 1.d4 d5 2.c4 e6.

Nicole Mollo Figueroa plays on top board and embodies the squad's steepest rating progression. Her median rating in the database stands at 1918, compared to her current 2110; her robust returns of 72.0% with White and 75.0% with Black were compiled largely against opposition rated nearly 200 points below her present standard. In round 7, against Alexandra Zherebtsova of Montenegro (2272), Mollo held a tablebase-winning rook, bishop, and pawn versus rook ending when she played 75.Rd6, leaving the rook en prise to the enemy king: 75...Kxd6 would have sealed an immediate draw. Her opponent, pressed with under 6 minutes on the clock, replied erroneously with 75...Kb8, after which Mollo still had to discover 78.a5, the only move preserving the technical win. She found it and converted the full point on move 85.

Daniela Cordero records 55.9% with White and only 39.6% with Black across 24 games. Against 1.d4 she scored 37.5% in 8 games, and against 1.c4, 25.0% in 4. Gloria Luz Yepez Montenegro reflects a comparable imbalance, posting 60.0% with White and 40.0% with Black over 30 games with each colour. Both players represent prime targets for the Brazilian team when holding the White pieces. Conversely, Jessica Molina demonstrates bilateral stability: 79.2% in 12 games with White and 64.3% in 14 with Black, deploying the Caro-Kann in 6 of her 9 games against 1.e4 (66.7%). Her 26-game record is the most compact in the squad.

Jhoana Velarde Alarcon is the squad's solitary proponent of 1.e4, adopting it in 15 of 16 White games for a 53.3% return. Her most vulnerable line emerges against the French Defence: 12.5% in 4 games, with one draw and three defeats. With Black she exhibits greater resilience, scoring 59.4% in 16 games, deploying the 2...e6 Sicilian in 6 of 8 games against 1.e4 and securing 80.0% in 5 encounters against 1.d4. A significant portion of the competitive history for Velarde, Mollo, Cordero, and Yepez stems from the Bolivian Championship finals, where they compete directly against one another.

Where the engine finds the errors

The table below details the average evaluation loss per move across each phase of play, alongside the volume of moves analysed in brackets. In the opening moves, all ten competitors maintain strict positional discipline, clustered tightly between 4 and 11 centipawns. Distinct tactical disparities emerge in the middlegame: the Greek grandmasters range from 13 (Theodorou) to 24 centipawns (Alexakis), whereas the Bolivian women's team spans from 29 (Mollo) to 42 (Cordero). This analytical divide indicates that preserving board complexity in the women's match offers Brazil the most fertile ground for tactical breakthroughs.

The most transparent example of clock-induced collapse occurred in Jessica Molina's clash with Oksana Golubeva in round 4. Conducting the White pieces, Molina enjoyed absolute parity (−0.07) when she committed the inaccuracy 26.Qf5+ with 3 minutes and 6 seconds on her clock, causing the evaluation to plunge to −6.45. Golubeva replied with 26...Kd8, letting the immediate tactical refutation slip, and three moves later dynamic balance was restored (−0.56). However, with 46 seconds remaining, Molina erred fatally with 29.Bf3, returning the evaluation to −6.63; this time Golubeva converted with precision. With 41 seconds on her clock, Molina blundered mate in one with 31.Qh5, allowing 31...Qxd1#. Golubeva, by contrast, maintained an ample cushion of over 20 minutes.

On the Greek side, the most pronounced calculation swings occurred without acute clock pressure. In round 8 against Semion Sapocinic of Moldova, Stamatis Kourkoulos-Arditis ventured 21...Ra3 with 48 minutes remaining, causing the evaluation to surge from +0.64 to +5.54 in White's favour. Sapocinic, however, countered with the inaccurate 22.Na2 (+0.20), when the energetic knight thrust 22.Ncb5 would have forced decisive gains, allowing the Greek grandmaster to regroup and prevail. Similarly, Ioannis Papaioannou succumbed to Aleksandar Indjic at the 2025 European Team Championship after playing 45.Qxc3 with 14 minutes in reserve, seeing his position deteriorate from −1.47 to −7.79.

Dimitris Alexakis provides a case study of managing zeitnot while securing victory. In round 5 against Hannes Stefansson of Iceland, two substantial advantages suffered compression: 61.Rd2, played with 36 seconds, reduced the evaluation from +7.37 to +3.65, and 67.Qe2, with 37 seconds, lowered it from +6.70 to +2.67. In round 8 against Dmitrii Gubin of Moldova, holding mate in 7, he opted for 59.f4 with 1 minute 31 seconds, maintaining an overwhelming advantage of +10.43. While he emerged victorious in each contest, the pattern indicates that Alexakis's technical conversion becomes more laborious as his clock depletes.

Three statistical averages in the table require nuanced context. Dimitrios Mastrovasilis's 53 centipawns in the endgame stem almost entirely from a queen versus rook ending contested in the Greek Team Championship; tablebase analysis confirms the position was theoretically won throughout, and he properly converted the point. Truncated engine searches penalize repetitive maneuvers that lengthen a mate without altering the objective result. The identical nuance explains Gloria Luz Yepez Montenegro's 93 centipawns, whose largest algorithmic deductions occurred in positions already mathematically won, such as her round 8 pawn ending against James of Trinidad and Tobago. Conversely, Daniela Cordero's 57 centipawns reflect authentic positional lapses: in the 2025 Bolivian Championship final against Barros Jardi, her move 50.Ke6, played with 4 minutes 20 seconds, converted a drawn 0.00 position into an irrecoverable −8.94 evaluation.

What the online accounts show, and what they do not

This analytical section is deliberately segregated from the classical assessment. Speed chess in rapid and blitz controls operates under different tactical dynamics: opening repertoires are inherently broader and more experimental, and decisions made under three-minute constraints rarely mirror classical preparation. Online games are useful for illuminating an athlete's intuitive familiarity with specific structures and revealing tactical discomfort, rather than forecasting specific opening choices over the board.

Nikolas Theodorou represents the most compelling instance of repertoire divergence. In classical competition, he opens 1.d4 in 21 of 28 games and 1.Nf3 in 6; online, 1.e4 emerges in 64 of his 115 White games. He maintains strong metrics with both colours, scoring 69% as White and 55% as Black. His most vulnerable online segment occurs with Black against 1.e4 d5 2.exd5 Qxd5 3.Nf3 in the Scandinavian Defence, where he recorded 25.0% over 6 games under medium confidence. As this chess opening does not appear in his classical tournament praxis, the finding is primarily of illustrative rather than preparational value.

Stamatis Kourkoulos-Arditis contested 25 games on the darkalekhine account, posting 55% with White and 61% with Black, while choosing 1.e4 in 8 of 11 White games in line with his classical repertoire. This constitutes too narrow a baseline for definitive tactical conclusions. Dimitrios Mastrovasilis (koutsalogo) and Dimitris Alexakis (tacticthunder) possess titled accounts that remained inactive during the evaluation window.

In the Bolivian squad, the titled accounts of Nicole Mollo Figueroa (nicky_mf), Gloria Luz Yepez Montenegro (gloriayepez), and Jessica Molina (jessy-molina) recorded between 2 and 6 games over the past 90 days, while Daniela Cordero's account (melian_9230) was inactive. Ioannis Papaioannou and Jhoana Velarde Alarcon have no confirmed accounts, and editorial standards exclude profiles whose ownership cannot be substantiated through official FIDE registration.

What to watch in round 9

In the open tournament, Brazil face an opponent holding higher average ratings on paper and demonstrated solidity when wielding the White pieces. The primary utility of this dossier lies in pinpointing setups where Greek effectiveness diminishes. Facing Mastrovasilis with White, the Sicilian Defence held undefeated across 12 games, yielding him only two victories alongside 10 draws. Against Alexakis, answering with 1...e5 2.Nf3 Nc6 reaches the segment where his return drops to 50.0% in 7 games, far below his 79.4% record against the Sicilian. Conversely, facing Kourkoulos-Arditis, 1...e5 constitutes his most lethal system (90.0% in 10), making the Sicilian a statistically sounder alternative (70.8% in 12). With White, 1.e4 e5 2.Nf3 Nf6 invites the Petroff Defence, where Theodorou managed only 30.0% in 5 games, while 1.d4 d5 2.c4 c6 tests the Slav Defence where Mastrovasilis scored 16.7% in 3. Against Alexakis, 1.d4 Nf6 2.c4 e6 held him to 37.5% across 4 games. While these subsets represent small samples flagged with low confidence, they provide valuable directional guidance.

In the women's event, Brazil enjoy clear technical favouritism and possess actionable statistical data for both colours. With Black, 1.d4 is virtually guaranteed on four boards, with only Velarde Alarcon likely to open 1.e4; against her, the French Defence represents her most vulnerable line, scoring 12.5% in 4 games. With White, the two Bolivians with the lowest returns, Yepez and Cordero, encounter persistent difficulty against 1.d4: Yepez scored 22.2% in 9 games and Cordero 37.5% in 8. If the French Defence arises, the Advance Variation (3.e5) has demonstrated clinical effectiveness, yielding 4 wins in 5 games against Yepez. Against Nicole Mollo, who handles the French with greater positional mastery, no simple shortcut exists: she recorded 65.4% in 13 games against 1.e4 and 81.3% in 8 against 1.d4.

Furthermore, the lessons of round 4 remain instructive: Canada were held to a 2-2 draw by this Bolivian team after Jessica Molina faltered in severe time trouble (zeitnot) from an equal position. In the women's event, the middlegame is where the Bolivians exhibit their highest evaluation loss; sustaining strategic tension and exerting clock pressure may ultimately prove more decisive than theoretical memorization of opening moves. As soon as the round commences and the official PGN confirms the starting line-ups, this article's dossier files will transition to displaying the four active boards and live games.

Frequently asked questions

Update log

• 2026-09-24 — First published, with the round 9 pairings checked on chess-results and the round still to be played: repertoire from 514 classical games broadcast on Lichess, error profile with Stockfish 19 at depth 16 and blitz and rapid repertoire from verified accounts. The dossiers cover both opponents' full squads; once the line-ups are out, the same file shows the four boards and the round's games.
• 2026-09-29 — The Olympiad ended on 27 September: Uzbekistan won the open and China the women's event. This coverage is no longer updated; the final result is in the standings story.

Sources

• 46th Chess Olympiad Samarkand 2026, Open: round 9 pairings — Chess-Results
• 46th Chess Olympiad Samarkand 2026, Women: round 9 pairings — Chess-Results
• Jessica Molina v Oksana Golubeva, round 4: broadcast game — Lichess
• Nicole Mollo Figueroa v Alexandra Zherebtsova, round 7: broadcast game — Lichess
• Nikolas Theodorou (nikotheodorou): titled profile confirming the account used in the online repertoire — Chess.com

Related guides

• How to build an opening repertoire: 1.c4 as White and the Sicilian as Black
• How to avoid time trouble in chess: five rules for the last three minutes
• Corporate chess leagues: what changes when the point belongs to the team