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Blackmar-Diemer Gambit Declined: O'Kelly Defense

258K games from Lichess · Updated January 2026

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Analyze this line move by move

Black expected score · All ratings · All speeds

45.1%

40%55%
Floor44.9%

the worst score you would still get, 90% confident. At best 45.2%.

Measured over 258K games at this level and clock.

Tough Sellloses more often than it wins at this level

Black comes out behind here — there are better weapons in the list.

Outcomes for Black

Draw 3.5 · Score = win + ½ of the draws · 258K games

Rank among the families Black can choose here
not ranked — this is a variation, not a family
Games in this context
258K
Best context
47.9% at 0-999 Rapid
Worst context
42.7% at 1200-1399 Blitz
Average game length
32 moves
Games that end decisively
96.5%
Draws
3.5%

Best and worst are the strongest and weakest squares with at least 500 games behind them. The table further down shows every square, including thinner ones.

Where it holds · Black score by rating × clock

Green is clearly ahead for Black, grey is around even, red is behind. Tap a cell to measure there, and again to clear. It falls away as the rating rises: 55.0% at 0-999, 34.4% at 2500+.

RatingUBBulleBlitzRapidClass
0-999
1000-1199
1200-1399
1400-1599
1600-1799
1800-1999
2000-2199
2200-2499
2500+—

Expected score matrix by rating bracket and time control

  • 0-999 rating, UltraBullet: 70.0% expected score (1 games)
  • 0-999 rating, Bullet: 47.7% expected score (944 games)
  • 0-999 rating, Blitz: 46.0% expected score (2,341 games)
  • 0-999 rating, Rapid: 47.9% expected score (1,491 games)
  • 0-999 rating, Classical: 63.4% expected score (6 games)
  • 1000-1199 rating, UltraBullet: 52.5% expected score (19 games)
  • 1000-1199 rating, Bullet: 45.3% expected score (2,095 games)
  • 1000-1199 rating, Blitz: 45.4% expected score (2,944 games)
  • 1000-1199 rating, Rapid: 46.0% expected score (1,691 games)
  • 1000-1199 rating, Classical: 54.9% expected score (50 games)
  • 1200-1399 rating, UltraBullet: 43.1% expected score (42 games)
  • 1200-1399 rating, Bullet: 45.7% expected score (4,658 games)
  • 1200-1399 rating, Blitz: 42.7% expected score (4,862 games)
  • 1200-1399 rating, Rapid: 47.2% expected score (2,021 games)
  • 1200-1399 rating, Classical: 44.5% expected score (62 games)
  • 1400-1599 rating, UltraBullet: 55.9% expected score (209 games)
  • 1400-1599 rating, Bullet: 43.4% expected score (7,838 games)
  • 1400-1599 rating, Blitz: 44.3% expected score (9,974 games)
  • 1400-1599 rating, Rapid: 44.4% expected score (2,846 games)
  • 1400-1599 rating, Classical: 53.8% expected score (117 games)
  • 1600-1799 rating, UltraBullet: 47.7% expected score (600 games)
  • 1600-1799 rating, Bullet: 44.3% expected score (14,222 games)
  • 1600-1799 rating, Blitz: 44.9% expected score (16,875 games)
  • 1600-1799 rating, Rapid: 45.1% expected score (4,390 games)
  • 1600-1799 rating, Classical: 46.2% expected score (141 games)
  • 1800-1999 rating, UltraBullet: 50.0% expected score (156 games)
  • 1800-1999 rating, Bullet: 44.3% expected score (26,555 games)
  • 1800-1999 rating, Blitz: 44.9% expected score (28,157 games)
  • 1800-1999 rating, Rapid: 44.9% expected score (4,756 games)
  • 1800-1999 rating, Classical: 42.2% expected score (158 games)
  • 2000-2199 rating, UltraBullet: 48.6% expected score (108 games)
  • 2000-2199 rating, Bullet: 44.8% expected score (39,360 games)
  • 2000-2199 rating, Blitz: 46.8% expected score (23,806 games)
  • 2000-2199 rating, Rapid: 44.6% expected score (2,636 games)
  • 2000-2199 rating, Classical: 53.0% expected score (49 games)
  • 2200-2499 rating, UltraBullet: 39.1% expected score (44 games)
  • 2200-2499 rating, Bullet: 45.2% expected score (37,100 games)
  • 2200-2499 rating, Blitz: 47.4% expected score (7,067 games)
  • 2200-2499 rating, Rapid: 47.3% expected score (551 games)
  • 2200-2499 rating, Classical: 21.5% expected score (2 games)
  • 2500+ rating, UltraBullet: 11.5% expected score (5 games)
  • 2500+ rating, Bullet: 44.5% expected score (6,920 games)
  • 2500+ rating, Blitz: 42.7% expected score (257 games)
  • 2500+ rating, Rapid: 38.9% expected score (3 games)

Related Openings

Variations (5)
Blackmar-Diemer Gambit Declined: Vienna Defense
49.4%
Blackmar-Diemer Gambit Declined: Weinsbach Defense
55.1%
Blackmar-Diemer Gambit Declined: Lamb Defense
47.6%
Blackmar-Diemer Gambit Declined: Langeheinicke Defense
49.4%
Blackmar-Diemer Gambit Declined: Elbert Countergambit
47.7%
Analyze Blackmar-Diemer Gambit Declined: O'Kelly Defense PositionsSee what each move is worth at your rating, move by move

Methodology

Across every rating and clock, the Blackmar-Diemer Gambit Declined: O'Kelly Defense scores 45.1% for Black — we are 90% confident the real figure is between 44.9% and 45.2% — from 258K Lichess games. Win rate, draw rate and loss rate come from games played December 2023 to November 2025.

How the figures are made
Whose games these are
258K+ rated games played on Lichess (2023-12 to 2025-11). The games are Lichess’s and free for anyone to use. What is ours is the reading of them. Last rebuilt January 2026.
Which games we count
  • Rated games only — nothing casual.
  • Both players within 200 rating points of each other. A mismatch tells you about the gap, not about the opening.
  • At least 2 moves played.
  • A game is filed under White’s rating.
Why every number comes with a range
A number off a few hundred games is a guess. The same number off millions is a fact. The range is what tells them apart, and it is what the lists rank on — so an opening cannot reach the top on a lucky run of forty games. The more games behind a figure, the narrower its range.
How much we need before we say anything
An opening page needs 100 games. A gambit needs 50 games at a rating before we will say whether it pays there. The chaos and trap lists need 500 games overall and 250 games at one rating or clock.

Frequently Asked Questions

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate?

Playing the Blackmar-Diemer Gambit Declined: O'Kelly Defense, Black wins 43.3%, draws 3.5% and loses 53.2%. Counting a draw as half a point, that is an Expected Score of 45.1%. It rests on 258K rated games from Lichess.

At what rating does the Blackmar-Diemer Gambit Declined: O'Kelly Defense perform best?

The Blackmar-Diemer Gambit Declined: O'Kelly Defense performs best for Black at 0-999, with an Expected Score of 47.0% (4.8K games) and the highest Floor of any rating with enough games to read.

Is the Blackmar-Diemer Gambit Declined: O'Kelly Defense better in blitz or rapid?

For Black, the Blackmar-Diemer Gambit Declined: O'Kelly Defense scores about the same in both: an Expected Score of 45.4% in Blitz (96K games) against 45.4% in Rapid (20K games).

How sharp is the Blackmar-Diemer Gambit Declined: O'Kelly Defense?

The Blackmar-Diemer Gambit Declined: O'Kelly Defense has a sharpness score of 96.5 (very decisive), meaning 96.5% of games end decisively. Average game length is 32 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 0-999?

At 0-999, Black wins 44.8%, draws 4.3% and loses 50.9%. Counting a draw as half a point, that is an Expected Score of 47.0%. It rests on 4.8K Lichess games, which average 28 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 1000-1199?

At 1000-1199, Black wins 43.9%, draws 3.4% and loses 52.7%. Counting a draw as half a point, that is an Expected Score of 45.6%. It rests on 6.8K Lichess games, which average 29 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 1200-1399?

At 1200-1399, Black wins 43.4%, draws 2.6% and loses 54.0%. Counting a draw as half a point, that is an Expected Score of 44.7%. It rests on 12K Lichess games, which average 28 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 1400-1599?

At 1400-1599, Black wins 42.8%, draws 2.6% and loses 54.6%. Counting a draw as half a point, that is an Expected Score of 44.1%. It rests on 21K Lichess games, which average 29 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 1600-1799?

At 1600-1799, Black wins 43.2%, draws 3.1% and loses 53.8%. Counting a draw as half a point, that is an Expected Score of 44.7%. It rests on 36K Lichess games, which average 30 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 1800-1999?

At 1800-1999, Black wins 43.0%, draws 3.2% and loses 53.8%. Counting a draw as half a point, that is an Expected Score of 44.6%. It rests on 60K Lichess games, which average 32 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 2000-2199?

At 2000-2199, Black wins 43.6%, draws 3.7% and loses 52.7%. Counting a draw as half a point, that is an Expected Score of 45.5%. It rests on 66K Lichess games, which average 33 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 2200-2499?

At 2200-2499, Black wins 43.3%, draws 4.3% and loses 52.3%. Counting a draw as half a point, that is an Expected Score of 45.5%. It rests on 45K Lichess games, which average 35 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate at 2500+?

At 2500+, Black wins 41.5%, draws 5.7% and loses 52.8%. Counting a draw as half a point, that is an Expected Score of 44.4%. It rests on 7.2K Lichess games, which average 40 moves.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate in UltraBullet?

In UltraBullet, Black wins 48.4%, draws 1.1% and loses 50.5%. Counting a draw as half a point, that is an Expected Score of 49.0%. It rests on 1.2K Lichess games.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate in Bullet?

In Bullet, Black wins 43.2%, draws 2.9% and loses 53.9%. Counting a draw as half a point, that is an Expected Score of 44.7%. It rests on 140K Lichess games.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate in Blitz?

In Blitz, Black wins 43.3%, draws 4.2% and loses 52.5%. Counting a draw as half a point, that is an Expected Score of 45.4%. It rests on 96K Lichess games.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate in Rapid?

In Rapid, Black wins 43.1%, draws 4.6% and loses 52.3%. Counting a draw as half a point, that is an Expected Score of 45.4%. It rests on 20K Lichess games.

What is the Blackmar-Diemer Gambit Declined: O'Kelly Defense win rate in Classical?

In Classical, Black wins 45.4%, draws 4.7% and loses 49.9%. Counting a draw as half a point, that is an Expected Score of 47.8%. It rests on 585 Lichess games.

Is the Blackmar-Diemer Gambit Declined: O'Kelly Defense a good opening?

The Blackmar-Diemer Gambit Declined: O'Kelly Defense is hard work for Black — it favours White. Across all ratings, Black wins 43.3% of its games and loses 53.2%. It performs best at 0-999. Your results depend on your rating, time control, and how well you know the typical plans.