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Blackmar-Diemer Gambit Declined: Lamb Defense

171K games from Lichess · Updated January 2026

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4...Nc6
Analyze this line move by move

Black expected score · All ratings · All speeds

50.4%

45%55%
Floor50.2%

the worst score you would still get, 90% confident. At best 50.6%.

Measured over 171K games at this level and clock.

Playablewins about as often as it loses at this level

Roughly even — the middlegame decides more than this opening choice does.

Outcomes for Black

Draw 4.0 · Score = win + ½ of the draws · 171K games

Rank among the families Black can choose here
not ranked — this is a variation, not a family
Games in this context
171K
Best context
54.5% at 0-999 Rapid
Worst context
45.4% at 2000-2199 Rapid
Average game length
31 moves
Games that end decisively
96.0%
Draws
4.0%

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.

Extra Analysis

Deep-dive datasets for this opening

Traps & Chaos

Complexity: 90.2 · Trap factor: +2.1 · 171K games

Time-Control Swing

Max swing: 12.2% · UltraBullet best · Classical worst

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 holds about the same all the way up, near 48.8%.

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: 27.0% expected score (5 games)
  • 0-999 rating, Bullet: 52.8% expected score (3,998 games)
  • 0-999 rating, Blitz: 53.6% expected score (12,807 games)
  • 0-999 rating, Rapid: 54.5% expected score (6,703 games)
  • 0-999 rating, Classical: 56.1% expected score (65 games)
  • 1000-1199 rating, UltraBullet: 45.9% expected score (35 games)
  • 1000-1199 rating, Bullet: 49.8% expected score (6,251 games)
  • 1000-1199 rating, Blitz: 50.3% expected score (14,143 games)
  • 1000-1199 rating, Rapid: 52.6% expected score (8,666 games)
  • 1000-1199 rating, Classical: 55.5% expected score (226 games)
  • 1200-1399 rating, UltraBullet: 33.7% expected score (69 games)
  • 1200-1399 rating, Bullet: 47.8% expected score (8,255 games)
  • 1200-1399 rating, Blitz: 50.4% expected score (13,256 games)
  • 1200-1399 rating, Rapid: 51.0% expected score (8,468 games)
  • 1200-1399 rating, Classical: 54.1% expected score (307 games)
  • 1400-1599 rating, UltraBullet: 48.8% expected score (82 games)
  • 1400-1599 rating, Bullet: 49.2% expected score (8,435 games)
  • 1400-1599 rating, Blitz: 49.9% expected score (13,770 games)
  • 1400-1599 rating, Rapid: 53.3% expected score (7,553 games)
  • 1400-1599 rating, Classical: 55.3% expected score (407 games)
  • 1600-1799 rating, UltraBullet: 43.1% expected score (113 games)
  • 1600-1799 rating, Bullet: 49.2% expected score (8,224 games)
  • 1600-1799 rating, Blitz: 50.3% expected score (11,250 games)
  • 1600-1799 rating, Rapid: 51.2% expected score (6,413 games)
  • 1600-1799 rating, Classical: 53.0% expected score (281 games)
  • 1800-1999 rating, UltraBullet: 41.3% expected score (27 games)
  • 1800-1999 rating, Bullet: 47.7% expected score (6,724 games)
  • 1800-1999 rating, Blitz: 49.1% expected score (7,448 games)
  • 1800-1999 rating, Rapid: 48.5% expected score (3,658 games)
  • 1800-1999 rating, Classical: 47.7% expected score (129 games)
  • 2000-2199 rating, UltraBullet: 59.1% expected score (15 games)
  • 2000-2199 rating, Bullet: 45.9% expected score (5,432 games)
  • 2000-2199 rating, Blitz: 48.1% expected score (2,944 games)
  • 2000-2199 rating, Rapid: 45.4% expected score (839 games)
  • 2000-2199 rating, Classical: 27.1% expected score (29 games)
  • 2200-2499 rating, UltraBullet: 67.4% expected score (10 games)
  • 2200-2499 rating, Bullet: 46.2% expected score (2,521 games)
  • 2200-2499 rating, Blitz: 46.5% expected score (563 games)
  • 2200-2499 rating, Rapid: 42.9% expected score (90 games)
  • 2200-2499 rating, Classical: 30.0% expected score (1 games)
  • 2500+ rating, UltraBullet: 50.0% expected score (2 games)
  • 2500+ rating, Bullet: 50.3% expected score (317 games)
  • 2500+ rating, Blitz: 48.8% expected score (38 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: O'Kelly Defense
53.2%
Blackmar-Diemer Gambit Declined: Langeheinicke Defense
49.4%
Blackmar-Diemer Gambit Declined: Elbert Countergambit
47.7%
Analyze Blackmar-Diemer Gambit Declined: Lamb Defense PositionsSee what each move is worth at your rating, move by move

Methodology

Across every rating and clock, the Blackmar-Diemer Gambit Declined: Lamb Defense scores 50.4% for Black — we are 90% confident the real figure is between 50.2% and 50.6% — from 171K 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
171K+ 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: Lamb Defense win rate?

Playing the Blackmar-Diemer Gambit Declined: Lamb Defense, Black wins 48.3%, draws 4.0% and loses 47.6%. Counting a draw as half a point, that is an Expected Score of 50.4%. It rests on 171K rated games from Lichess.

At what rating does the Blackmar-Diemer Gambit Declined: Lamb Defense perform best?

The Blackmar-Diemer Gambit Declined: Lamb Defense performs best for Black at 0-999, with an Expected Score of 53.7% (24K games) and the highest Floor of any rating with enough games to read.

Is the Blackmar-Diemer Gambit Declined: Lamb Defense better in blitz or rapid?

For Black, the Blackmar-Diemer Gambit Declined: Lamb Defense scores higher in Rapid: an Expected Score of 50.6% in Blitz (76K games) against 52.0% in Rapid (42K games).

How sharp is the Blackmar-Diemer Gambit Declined: Lamb Defense?

The Blackmar-Diemer Gambit Declined: Lamb Defense has a sharpness score of 96.0 (very decisive), meaning 96.0% of games end decisively. Average game length is 31 moves.

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

At 0-999, Black wins 51.1%, draws 5.2% and loses 43.7%. Counting a draw as half a point, that is an Expected Score of 53.7%. It rests on 24K Lichess games, which average 29 moves.

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

At 1000-1199, Black wins 48.7%, draws 4.4% and loses 46.9%. Counting a draw as half a point, that is an Expected Score of 50.9%. It rests on 29K Lichess games, which average 30 moves.

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

At 1200-1399, Black wins 48.0%, draws 3.8% and loses 48.3%. Counting a draw as half a point, that is an Expected Score of 49.9%. It rests on 30K Lichess games, which average 30 moves.

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

At 1400-1599, Black wins 48.8%, draws 3.5% and loses 47.7%. Counting a draw as half a point, that is an Expected Score of 50.6%. It rests on 30K Lichess games, which average 30 moves.

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

At 1600-1799, Black wins 48.4%, draws 3.6% and loses 48.0%. Counting a draw as half a point, that is an Expected Score of 50.2%. It rests on 26K Lichess games, which average 32 moves.

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

At 1800-1999, Black wins 46.6%, draws 3.7% and loses 49.7%. Counting a draw as half a point, that is an Expected Score of 48.5%. It rests on 18K Lichess games, which average 33 moves.

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

At 2000-2199, Black wins 44.4%, draws 4.2% and loses 51.4%. Counting a draw as half a point, that is an Expected Score of 46.5%. It rests on 9.3K Lichess games, which average 34 moves.

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

At 2200-2499, Black wins 43.8%, draws 4.8% and loses 51.4%. Counting a draw as half a point, that is an Expected Score of 46.2%. It rests on 3.2K Lichess games, which average 35 moves.

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

At 2500+, Black wins 47.6%, draws 5.2% and loses 47.3%. Counting a draw as half a point, that is an Expected Score of 50.2%. It rests on 357 Lichess games, which average 38 moves.

What is the Blackmar-Diemer Gambit Declined: Lamb Defense win rate in UltraBullet?

In UltraBullet, Black wins 43.5%, draws 0.4% and loses 56.1%. Counting a draw as half a point, that is an Expected Score of 43.7%. It rests on 358 Lichess games.

What is the Blackmar-Diemer Gambit Declined: Lamb Defense win rate in Bullet?

In Bullet, Black wins 47.2%, draws 2.7% and loses 50.1%. Counting a draw as half a point, that is an Expected Score of 48.6%. It rests on 50K Lichess games.

What is the Blackmar-Diemer Gambit Declined: Lamb Defense win rate in Blitz?

In Blitz, Black wins 48.3%, draws 4.5% and loses 47.2%. Counting a draw as half a point, that is an Expected Score of 50.6%. It rests on 76K Lichess games.

What is the Blackmar-Diemer Gambit Declined: Lamb Defense win rate in Rapid?

In Rapid, Black wins 49.6%, draws 4.8% and loses 45.7%. Counting a draw as half a point, that is an Expected Score of 52.0%. It rests on 42K Lichess games.

What is the Blackmar-Diemer Gambit Declined: Lamb Defense win rate in Classical?

In Classical, Black wins 50.6%, draws 5.6% and loses 43.9%. Counting a draw as half a point, that is an Expected Score of 53.4%. It rests on 1.4K Lichess games.

Is the Blackmar-Diemer Gambit Declined: Lamb Defense a good opening?

The Blackmar-Diemer Gambit Declined: Lamb Defense is about level. Across all ratings, Black wins 48.3% of its games and loses 47.6%. It performs best at 0-999. Your results depend on your rating, time control, and how well you know the typical plans.