ECO Families

Family-level performance, tier mix, trend direction, and engine–human outliers across the tracked opening set.

Tracked Openings

498

Weighted Avg Win Rate

49.09%

Rising Openings

34

Avg Engine Gap

3.19 pp

Family B has the lowest win rate across all openings

49.5%
A
48.1%
B
49.3%
C
49.2%
D
49.5%
E

Opening Families

A

ECO A

100 openings

Flank Openings

T144T215T341

AVG WIN RATE

49.46%

43.92% – 54.33%

TRENDS

↑ 7 → 82 ↓ 11

ENGINE GAP

−1.1 pp

FORECAST CONFIDENCE

high18med24low17

REGIME CHANGES

8 detected

TOP OUTLIER

A44
Benoni Defense: Old Benoni
-11.02 pp
B

ECO B

100 openings

Semi-Open Games

T151T211T338

AVG WIN RATE

48.11%

40.47% – 55.89%

TRENDS

↑ 13 → 83 ↓ 4

ENGINE GAP

−3.0 pp

FORECAST CONFIDENCE

high18med27low17

REGIME CHANGES

10 detected

TOP OUTLIER

B29
Sicilian Defense: Nimzowitsch Variation
-10.88 pp
C

ECO C

100 openings

Open Games

T152T210T338

AVG WIN RATE

49.25%

42.96% – 55.30%

TRENDS

↑ 8 → 82 ↓ 10

ENGINE GAP

−1.5 pp

FORECAST CONFIDENCE

high12med33low17

REGIME CHANGES

16 detected

TOP OUTLIER

C40
Elephant Gambit
-10.75 pp
D

ECO D

98 openings

Closed / Semi-Closed

T139T213T346

AVG WIN RATE

49.16%

45.30% – 54.13%

TRENDS

↑ 4 → 87 ↓ 7

ENGINE GAP

−1.2 pp

FORECAST CONFIDENCE

high6med31low15

REGIME CHANGES

11 detected

TOP OUTLIER

D44
Semi-Slav Defense Accepted
-6.93 pp
E

ECO E

100 openings

Indian Defenses

T130T215T355

AVG WIN RATE

49.46%

45.61% – 54.65%

TRENDS

↑ 2 → 93 ↓ 5

ENGINE GAP

0.1 pp

FORECAST CONFIDENCE

high8med25low12

REGIME CHANGES

6 detected

TOP OUTLIER

E98
King's Indian Defense: Orthodox Variation, Classical System
+8.52 pp

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