Canada's round 5 opponents at the Olympiad: how Spain and Costa Rica play

Short answer

In round 5 of the 46th Chess Olympiad, on 20 September 2026, Canada play Spain on board 10 of the open section and Costa Rica on board 29 of the women's. Drawing on 841 classical games broadcast by Lichess over the last three years, this piece lays out each player's repertoire in both squads, the lines where they score below their own average, where the engine finds the mistakes — with every quoted move re-measured at depth 24 — and what the verified online accounts show, including the one that was left out.

Event: 46th FIDE Chess Olympiad

How this was compiled: Compiled on 19 September 2026, with round 4 finished and round 5 not yet played: it starts on 20 September at 3pm Samarkand time (10:00 UTC). The pairings were checked on chess-results; the official PGN that names each team's line-up is only published when the round starts, so this dossier covers both full squads rather than four boards each. The repertoire uses over-the-board classical games from the last three years broadcast by Lichess, linked to each player by FIDE ID and excluding round 5 itself: 458 games across the five Spanish players (76 to 118 each) and 383 across the five Costa Rican players (26 to 131). Chess960 games were excluded from the classical sample starting this round. The error profile was measured with Stockfish 19 at depth 16 over each player's 12 most recent classical games, and every move quoted in the text was re-measured at depth 24 with a dedicated search. The blitz and rapid repertoire comes from Chess.com accounts verified one by one, over the last 90 days; three of the ten players have games in the window, and Daniil Yuffa was left out for want of account verification.

The essentials in a few lines

• In round 5, on 20 September 2026, Canada play Spain on board 10 of the open section and Costa Rica on board 29 of the women's, level on match points in both.
• Four of the five Costa Rican players open 1.e4 in 94% or more of their White games, two of them in 100%. Against three of the five the dossier recommends 1.d4: 41.7% in 18 games, 40.9% in 11 and 36.4% in 11.
• David Antón Guijarro and Maksim Chigaev give way in the same place, the open games: after 1.e4 e5 2.Nf3 Nc6 he scores 25.0% in 10 games and Chigaev 28.6% in 7. Antón's drop is the largest of the round, almost 35 percentage points.
• Daniil Yuffa carries the best-sampled edge on the Spanish side — 37.5% in 16 games against 1.d4, at high confidence — and is precisely the player left without an online section, because his account did not meet the verification standard.
• Jaime Santos Latasa has the lowest centipawn loss of the entire round, 12 per move, with 6 in the endgame. At the other end, María Elena Rodríguez Arrieta's endgame costs 51.
• The figures are from the opponent's point of view and hold as tendencies: samples from 26 to 131 games, an error profile over 12 games per player, and every percentage carries the number of games behind it.

The round 5 picture

Canada arrives on 6 match points in the open section after beating Kosovo 3-1, and on 5 in the women's after drawing 2-2 with Bolivia. Both opponents sit on the same match points, with Canada ahead on game points in both: 12 to 11 against Spain, and 11.5 to 9 against Costa Rica.

The two matches could hardly be more different in shape. Spain fields five grandmasters, all between 2570 and 2632, the tightest rating band Canada has faced in this Olympiad. Costa Rica's five span 352 rating points, from 2189 down to 1837. One match is a wall of equals; the other is a staircase.

Spain is also the one opponent Canada meets whose squad has already appeared in this series. The Spanish women's team played the United States in round 4 — a different set of players entirely, which is why none of the names below carries over from that dossier.

The sample column says how much of each dossier holds up. Daniil Yuffa brings 118 classical games and Sofía Mayorga Araya 131, the two largest here; Olga Leticia Gamboa Alvarado has 26, the smallest of the match and the only one close to the line where the dossier starts flagging low confidence. The totals are 458 games for Spain and 383 for Costa Rica, all over the board and broadcast publicly by Lichess in the last three years.

Spain: five grandmasters, two of them uneasy in the open games

The coincidence between Antón Guijarro and Chigaev is the most quotable thing in the Spanish half of this dossier, and it needs stating carefully. Both are struck in the same place — the open games, 1.e4 e5 2.Nf3 Nc6 — and in both cases against their own baseline: Antón at 25.0% in 10 games against a 59.8% average with Black, Chigaev at 28.6% in 7 against 51.2%. Antón's is the larger drop in the whole round, almost 35 percentage points, and both are marked medium confidence. Two players is not a pattern, but it is the kind of thing a team captain checks twice.

Daniil Yuffa is the best-documented Spaniard, with 118 games, and the one whose edge is best sampled: against 1.d4 he scores 37.5% in 16 games, against his own 52.6% with Black, at high confidence. He is also the squad's most varied first-mover, splitting White between 1.c4 in 24 games, 1.Nf3 in 17 and 1.d4 in the rest — and after 1.Nf3 he drops to 44.4% in 9 when the reply is 1...d5.

Jaime Santos Latasa carries the strongest White figures in the match, 73.8% across 40 games, and the dossier finds almost nothing to say against him: the best it offers is 1.c4, which gave him 33.3% in 3 games — three games, low confidence, and not a plan. With Black against his 1.e4 the record is a little better sampled: 1...e5 held him to 57.1% in 7.

Alexei Shirov, at 53, is the player here whose name needs least introduction and whose dossier says least. Across 76 games he has no first move that beats his own baseline with Black — against 1.e4 he actually scores 61.1% in 18 games, above his 55.6% average — and with White he splits 1.e4 in 26 games and 1.d4 in 12, at 59.6% and 70.8%. A dossier that points at nothing is not a failed dossier; it is a dossier saying the opponent is solid in both colours.

Costa Rica: all five open 1.e4, and the dossier answers 1.d4

A squad where four of five players open the same move in 94% of their games or more is not a coincidence of taste, and the mirror image of that uniformity is what makes this section unusual: against three of those four, the recommendation is also the same move. Preparing for this match with the white pieces costs Canada one line of study repeated three times, which almost never happens.

Sofía Mayorga Araya is the squad's top board and its largest sample, 131 games — more than any Spaniard on the other match. She opened 1.e4 in 64 of 66 White games and scores 63.6% with them, against 53.1% with Black. The edge against her is the best sampled of either match: 1.d4 held her to 41.7% in 18 games, at high confidence. With Black against her 1.e4, 1...e5 held her to 50.0% in 15, also high confidence — two usable lines on the same player, which is rare.

Valentina Campos Muñoz and María Elena Rodríguez Arrieta repeat the shape with smaller samples. Campos Muñoz opens 1.e4 in 45 of 48 and gives up 40.9% in 11 games against 1.d4; Rodríguez Arrieta opened 1.e4 in all 35 of her White games and gives up 36.4% in 11. Against Rodríguez Arrieta's 1.e4 the Caro-Kann is on record at 40.0%, but on only 5 games, which the dossier marks low confidence and this text repeats for the same reason.

The two at the bottom of the rating list are the two the dossier treats most carefully. Victoria Canales Chinchilla also opened 1.e4 in all 32 of her White games, and scores 67.2% with them against 40.9% with Black — the widest gap between colours in the match. Olga Leticia Gamboa Alvarado is the exception to the squad's first move, opening 1.d4 in 7 of her 11 White games, and she has 26 games in total. That is the smallest sample of the round, and it is why no weak line of hers appears here.

Where the engine finds the mistakes

The table gives average centipawn loss per move by phase. The opening column runs from 5 to 10 across all ten players, and as always it describes preparation more than play. What happens afterwards separates the two squads more sharply than in any other match of this round.

The Spanish endgames are the story. Santos Latasa at 6 and Antón Guijarro at 7 are the two cleanest endgame figures in the whole series so far, and they are not built on tiny samples — 175 and 87 endgame moves respectively. Chigaev, Shirov and Yuffa sit at 27, 29 and 29, which is ordinary for grandmasters in this sample. It is worth saying plainly that a 12-game window is a window: these numbers describe a recent stretch, not a permanent property, and five centipawns between two names mean nothing at all.

On the Costa Rican side the figures are uniformly higher, which is what a 350-point rating difference looks like when measured in centipawns rather than in results. The one worth isolating is Rodríguez Arrieta: 41 in the middlegame and 51 in the endgame, over 102 endgame moves. It is the highest endgame figure of the round, and unlike some of the high numbers elsewhere in this series it does not dissolve on inspection — her worst moments are spread across games rather than concentrated in one already-decided position.

That distinction matters more than it sounds. In this round's re-measurement at depth 24, several of the most expensive moves flagged at depth 16 turned out to sit in positions that were already won or already lost, where a shallow ruler charges fortunes for moves that change no result. No worst moment reaches this text without that check.

Blunder counts stay out of the table for the related reason: the classification uses uncapped loss, so a winning player who picks a slower mate collects a blunder for a move that changes nothing. Average centipawn loss caps each evaluation at 1000 and does not suffer from it.

The online repertoire, and the account that was left out

Yuffa's case is worth explaining, because leaving a player out is a decision and decisions should be shown. There is a Chess.com account under his exact name with a platform-verified GM title, and there is exactly one GM in the world called Daniil Yuffa. What does not match is the country: the profile declares Russia, and his FIDE registration is Spanish. He is Russian-Spanish and transferred federations, so the mismatch has an innocent explanation — but an innocent explanation is not a proof, and no official source was found linking that account to the player. The rule for this series is that a doubtful account does not enter, because attributing the wrong account publishes a stranger's repertoire under an athlete's name.

For comparison, the account that did enter with an unusual proof belongs to Alexander Donchenko, in the American dossier of this same round: his profile also declares the wrong country, but Chess.com's own player page links to the member account, and a platform vouching for its own user is evidence of a different order from a name that happens to match.

What the three usable accounts show is recency rather than surprise. Antón Guijarro's 300 games are heavily King's Pawn on both sides — the Sicilian is his most played White opening at 11 games, and King's Pawn Game openings account for his top two with Black, 25 and 9 games. Santos Latasa's 152 lean the other way, with Indian and Queen's Pawn structures at the top of his White list. Chigaev has 25 games, a sample the dossier itself treats as thin, and it is quoted here only with that label attached.

None of it is merged into the classical numbers. These are blitz and rapid games, and in a classical Olympiad game with 90 minutes and an increment the repertoire that counts is the one from the board. The online record is here because it answers a different question — what someone plays when nothing is at stake — and because saying so is cheaper than pretending the two are the same.

What to watch in round 5

It is worth separating what the dossier does from what it does not. It shows where an opponent has scored below their own recent average, with the sample size attached. It does not say what the Canadian players are good at, does not measure anyone's form this week, and does not predict a result. The two only meet when the line where the opponent scores less is also one your own side wants to play.

The women's match is the unusual one. Costa Rica's uniformity at move one means Canada's preparation with Black converges on a single first move to meet, and its preparation with White converges on a single first move to play. Sofía Mayorga Araya is the one player of the five against whom the dossier offers a high-confidence line in both colours: 1.d4 with White, and 1...e5 against her 1.e4 with Black, at 50.0% in 15 games.

In the open section, the honest summary is that five grandmasters within 62 rating points of each other do not leave much on the table. Yuffa's 37.5% against 1.d4, in 16 games at high confidence, is the best-sampled edge; the open-game figures of Antón Guijarro and Chigaev are larger drops on smaller samples. Santos Latasa, with the squad's best White score and the round's lowest centipawn loss, is the board where the dossier is quietest — which, in a match of equals, is its own kind of warning.

One closing caution. These are two matches on equal match points, and a dossier describes the recent past, not tomorrow's board. In round 4 Canada beat Kosovo 3-1 in the open section and drew 2-2 with Bolivia in the women's, and neither result was written in the numbers beforehand — because that is not what the numbers are for.

Frequently asked questions

Update log

• 2026-09-19 — Initial publication, with the round 5 pairings checked on chess-results and the round not yet played: repertoire from classical games broadcast by Lichess, error profile with Stockfish 19 at depth 16, quoted moves re-measured at depth 24 and a blitz and rapid repertoire from verified online accounts. The dossiers cover both full squads; once the line-ups are out, the same file will show the four boards and the round's game.
• 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 5 pairings — Chess-Results
• 46th Chess Olympiad Samarkand 2026, Women — round 5 pairings — Chess-Results
• Sofía Mayorga Araya — broadcasts under FIDE ID 6514065 — Lichess
• David Antón Guijarro (tptagain) — titled profile that verifies the account used for the online repertoire — Chess.com

Related guides

• How to build an opening repertoire: 1.c4 as White and the Sicilian as Black
• Corporate chess leagues: what changes when the point belongs to the team
• An open games repertoire: meeting 1.e4 with 1...e5 without memorising Ruy Lopez theory