Decision-making training for serious chess players

You already know chess.
You don't know why you lose.

Chess By Principle finds the recurring patterns in your games—the decisions that keep costing you points—and trains you to make better ones. No engine scores. No centipawns. Coaching language that builds the thinking process strong players use.

5 games/month free. No credit card required.

The problem

You analyze your games.
You still make the same mistakes.

The engine tells you Nd5 was better. It doesn't tell you why you didn't see it—or what you were thinking when you played something else. Knowledge of the right move isn't the same as the process that finds it.

What engines give you
Move 14: +2.3 → +0.8 (blunder)
Best move was Nd5 (+2.1)
Move 18: −0.4 (inaccuracy)
Accuracy: 74.2%

You now know what went wrong. You don't know why you thought what you did was right—so next week, you do it again.

What Chess By Principle gives you
Your bishop on c1 is a tall pawn. Open the diagonal or trade it before you do anything else.
Your rooks are sleeping. The e-file is open—both rooks belong there.
You skipped Step 1. Before Bd3, you had Nxf7—check, capture, and fork. Find forcing moves first.

You now know what step you skipped, and why it cost you. That's what sticks.

The Pilot Checklist

Every move. Three questions. In order.

Strong players don't calculate randomly. Before every move, they run the same process—every time, without exception.

1
Checks, captures, threats.
Find every forcing move available—yours and your opponent's. All of them. Before anything else. Most mistakes happen because this step was skipped.
2
What's the most forcing continuation?
If you have a forcing move, find the best one. If you don't, that tells you something too—the position is asking you to improve a piece, not calculate.
3
Activate your worst piece.
No forcing moves? Find the piece doing the least work. Put it somewhere better. Every move should make your position harder to play against.

After every game you analyze, we show you which step you skipped—and on which move.

Your coaching report

This is what coaching language looks like.

Every lesson in your report is tied to a specific move, a specific principle, and what to do differently next time.

Piece Activity
Move 11
Your bishop is a tall pawn.
The bishop on c1 has no diagonals. It's blocked by your own pawns and doing nothing. Before you develop anything else, open that diagonal or trade the bishop off. A piece with no scope is a liability, not an asset.
Pilot Checklist—Step 1
Move 14
You skipped checks and captures.
Before playing Bd3, you had Nxf7—a check that wins the exchange. You went for development when the position was asking for something forcing. Step 1 always comes first: find what's immediately available before planning.
Rook Activity
Move 19
Your rooks are sleeping.
Both rooks are still on their starting squares. The e-file has been open for four moves. Rooks are worthless on closed files—they belong on open ones. Double on the e-file and make your opponent deal with real pressure.
King Safety
Move 22
You delayed castling too long.
Your king is still in the center with the e-file open. Your opponent has two pieces pointed at it and hasn't committed to queenside yet. King safety is evaluated before material and piece activity—an exposed king changes everything.
The coaching framework

The position decides what matters.

There is no fixed priority order. King safety, material, piece activity, pawn structure—these four always apply, but the position determines which one to evaluate first. We read the position type before we apply the framework.

Tactical / Open
Open files, uncastled kings, forcing moves available
King Safety → Tactics → Piece Activity → Material
Positional / Closed
Locked pawns, maneuvering phase, no immediate threats
Piece Activity → Pawn Structure → Material → King Safety
Attack in Progress
Clear initiative, pieces aimed at king
Initiative → King Safety → Piece Activity → Material
Material Imbalance
Significant exchanges, compensation questions
Compensation → Piece Activity → King Safety → Pawn Structure
Endgame
Most pieces off board, kings active
King Activity → Pawn Structure → Material → Piece Activity
Adaptive memory

The coaching compounds.

After every game, your coaching profile updates. Recurring weaknesses get tracked by name—not just flagged once and forgotten. The third time your rook stays on its starting square past move 15, we call it out directly.

Over time, your profile builds a picture of how you actually play—your preferred openings, your strongest and weakest skill areas, where your thinking process breaks down. A coach that remembers every game you've ever played.

Recurring weakness
Sleeping rooks
4 games
HIGH
Recurring weakness
Delayed castling
3 games
HIGH
Strength identified
Knight outpost recognition
5 games
Opening tracked
Sicilian Defense, Najdorf
6 games played
Skill rating
King Safety: 6.2 / 10
trending up
The science

Why consistency compounds.
Why understanding the why matters.

Most chess improvement programs focus on what you should have played. CBP is built around a different question: why did you think your move was right? That distinction is the entire gap between knowledge and skill.

01
Deliberate practice requires feedback—not more games.
Ericsson's research on expertise is unambiguous: playing without targeted feedback doesn't build skill. It reinforces existing habits—including bad ones. Ten thousand games with no feedback encodes your current mistakes at a deeper level. CBP is the feedback layer. Without it, your passive rook rate stays exactly the same regardless of how much you play.
Ericsson et al.—Psychological Review, 1993
02
Spaced repetition is why the pattern tracker works.
Seeing a concept once in one game doesn't encode it. Seeing the same pattern called out in game 3, then game 7, then game 11—spaced across real positions with real consequences—does. Your coaching profile isn't just memory. It's a spaced-repetition engine for your specific error patterns. The third time your rook is flagged, the feedback lands differently than the first.
Ebbinghaus spacing effect—Journal of Experimental Psychology, 1913
03
Process beats outcome. Always.
Players who internalize a decision process—what to look for, in what order, before every move—outperform players who memorize correct moves in specific positions. One is a general algorithm that transfers to any board. The other is a library of solutions that doesn't. This is why CBP never uses centipawns. You cannot internalize a number. You can internalize "find every forcing move before you plan."
Kahneman, Thinking Fast and Slow—2011
04
Consistency is the variable that separates improving players from stagnating ones.
Small, regular engagement with your patterns—one game reviewed, one principle applied—compounds faster than occasional intensive study sessions. Your coaching profile gets more accurate over time. The recurring weakness that appears 8 times is diagnosed with more precision than the one that appeared once. The streak isn't a gimmick. It's a proxy for the compounding that's actually happening.
Duhigg, The Power of Habit—2012
Pricing

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5 games/month
Full coaching report
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Board viewer
Pilot Checklist feedback
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$12
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30 games/month
Adaptive coaching memory
Pattern report
Opening recognition
Stockfish engine panel
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$30
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150 games/month
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Deep Analysis per lesson
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