Chess Stalker — Free Chess Opponent Analysis

Analyze any Lichess, Chess.com or FIDE player's openings, weaknesses, blunder patterns and psychological profile. Train against a Twin Bot that replicates your opponent's style. Search by username or FIDE ID across 11 million+ games. Free to use, no signup required.

What you get

Opponent weakness analysis — opening repertoire, common blunders, time pressure patterns
Twin Bot — practice against an AI clone of your opponent's exact playing style
FIDE OTB database — 11 million+ tournament games and 1.7 million+ rated players
Stockfish-powered analysis with depth-25 evaluations
Multi-platform: Lichess, Chess.com, and FIDE in one place
Head-to-head comparison, Nemesis detection, Stalker Score

How it works

Search any Lichess, Chess.com username or FIDE player
Get instant scouting report with weaknesses and patterns
Prepare your strategy and practice against the Twin Bot

GM

Lupulescu, Constantin

ROU ROU·Born 1984·FIDE #1207822·2,614 Games

Classical25772,403 Games

Rapid2524123 Games

Blitz2548107 Games

Statistics

2614

Total

1073

Wins

1206

Draws

335

Losses

41%46%13%

Play Style

What you need to know before facing them

Elite accuracy: 94.3% average

Solid conversion: 81%

Very consistent (88%)

Very precise: only 0.1 blunders/game

Dominates 1.f4 ♔ (92% in 12 games)

Deep Analysis

Stockfish 18 · Classical games · 537 analyzed

Accuracy by phase

Opening97.0%

Middlegame94.1%

Endgame95.8%

Clutch Factor

Performance under pressure

+6%

Winning (+2 or more)95%

179 Games

Equal position96%

263 Games

Losing (-2 or more)89%

58 Games

Problematic Pieces

Which pieces cause most errors?

♖

22%

65 errors

♕

21%

61 errors

♙

16%

45 errors

♗

15%

43 errors

♞

13%

39 errors

♔

12%

36 errors

Critical Moment

When does the first serious error occur?

Move 39average

1-15

16-25

26-35

36-45

46+

35% of blunders occur between move 46+. Keep tension until that moment.

Error Heatmap

Where do most errors occur?

8

8

10

9

8

10

9

7

8

9

abcdefgh

Many

Few

Critical squares

b310 err

e510 err

c39 err

d49 err

e19 err

b3/e5 concentrate most errors. Force decisions in those zones.

Recent Games

W

Salimova, Nurgyul2404

Grand Prix Bucharest 2026 · 10 May 2026

0-1

D

Mamedov, Rauf2636

Grand Prix Bucharest 2026 · 10 May 2026

½-½

W

Ovezdurdyyeva, Jemal2213

Grand Prix Bucharest 2026 · 10 May 2026

0-1

D

Henriquez Villagra, Cristobal2603

Grand Prix Bucharest 2026 · 10 May 2026

½-½

D

Ivanchuk, Vasyl2634

Grand Prix Bucharest 2026 · 10 May 2026

½-½

D

Nevednichy, Vladislav2441

Grand Prix Bucharest 2026 · 10 May 2026

½-½

Openings

Based on player games

Weaknesses

EXPLOIT!

White

King's Indian: Classical

42.1%

19 Games·Loses

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Be2

Black

No significant weaknesses detected as Black

Strengths

AVOID

White

Caro-Kann: Advance

60.0%

10 Games·Wins

1.e4 c6 2.d4 d5 3.e5

Sicilian: Taimanov

55.0%

20 Games·Wins

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6

Black

Sicilian: Classical

46.5%

99 Games·Wins

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6

Reti: Gambit

53.8%

13 Games·Wins

1.Nf3 d5 2.c4 e6

Critical Blunders

Tactical errors analyzed with Stockfish

10 errors

▶

#39a6??

Tactics

vs Sjugirov

OTB·2025

▶

#55Rf5??

Endgame

vs Korobov

OTB·2025

▶

#59Bxa3??

Endgame

vs Yuffa

OTB·2025

▶

#15Qd5??

Tactics

vs Vijayakumar

OTB·2025

▶

#23a5??

Tactics

vs Cnejev

OTB·2024

▶

#49Kf7??

Endgame

vs Manolache

OTB·2024

▶

#58Ra1??

Endgame

vs Manolache

OTB·2024

▶

#68Ke4??

Endgame

vs Stanciu

OTB·2024

▶

#45Rb7??

Endgame

vs Bednarich

OTB·2024

▶

#40Ke4??

Endgame

vs Li

OTB·2024

Endgame Statistics

23 endgame categories analyzed — discover where they collapse under pressure

Repertoire

☰ All

♟ Classical

⚡ Rapid

🔥 Blitz

PRO

·

2026

2025

2024

2023

2022

2021

PRO

8

7

6

5

4

3

2

1a

b

c

d

e

f

g

h

Starting Position

1301 Games

47%44%9%

Move	Games	Performance	%
1.e4 Strong	621		72%
1.d4	507		66%
1.Nf3 Strong	83		71%
1.c4	77		64%
1.f4 Strong	12		92%
1.b3 Strong	1		100%

1.e4

72%

621

1.d4

66%

507

1.Nf3

71%

83

1.c4

64%

77

1.f4

92%

12

1.b3

100%

1

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