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Open a library or create a new game to see signals.
Most chess software focuses on finding the best move. ChessSignals focuses on helping you understand the position — highlighting the important features in plain English so you can see what matters without calculating everything yourself.
Instead of showing long engine variations, ChessSignals highlights the tactical and strategic features that strong players notice naturally:
The goal is understanding rather than memorising.
Use the Library tab to open a game library, or select a game from an existing library.
You can also use the Workspace tab to create a new game, build a position, or load a FEN or PGN.
Click any move in the move list on the right, or use the left and right arrow keys. The board and Signals update automatically.
The Signals tab explains what matters in the current position. Signals are grouped into four categories: Urgent, Defence, Attack, Background. Start with Urgent, then work down.
Library games cannot be edited in place. If you enter a move or modify a position, ChessSignals automatically creates a Workspace copy so you can analyse freely without affecting the original. Your own library files can still have games added to them from Workspace using Copy to Library on any workspace game's menu.
Use the 🎨 button on the right edge to adjust board colours, piece style, text size, signal display, and piece opacity.
The Workspace tab can be used to create or edit positions:
Start from the normal chess starting position.
Place pieces manually to create any position.
Paste a FEN string and analyse a single position.
Paste or import a complete PGN game.
The Library tab can be used to open or import collections of games:
In the Library tab, use the Open ▾ menu to open a PGN file from your device, create a new library, reopen a recent one, or load a built-in example (such as Morphy's games).
The Open ▾ menu also has Import games…. Choose a source (Chess.com or Lichess), enter a username, optionally pick a game type (Daily / Rapid / Blitz / Bullet) and a maximum number of games, and ChessSignals downloads that player's games into a new library you can browse and analyse. They can be your own games or anyone else's. (Saving the imported library to a file uses Chrome or Edge; other browsers keep it for the current session.)
The move list on the right is fully interactive. You can:
The Signals update automatically for the selected position.
Next to the move list (top right) is a Compare tab. It shows how the signals changed from the previous position to the current one:
This lets you see exactly what a move altered without re-reading the whole Signals list. In Predict mode, Compare instead shows your move against the game move.
Chess positions can contain a large amount of information. To reduce information overload, ChessSignals organises signals into four groups. Each group has its own colour, shown as a strip beside each signal: Urgent red, Defence amber, Attack green, Background grey.
Things that may require action immediately: checks, checkmate threats, captures available now, immediate tactical threats, fork opportunities. When a checkmate is available, only Urgent signals are shown.
Things affecting your safety: loose pieces, pinned pieces, x-rayed pieces, king safety issues, opponent passed pawns.
Opportunities against your opponent: their loose pieces, their pinned pieces, their king weaknesses, your passed pawns, tactical opportunities.
Longer-term positional features: development issues, overloaded pieces, strategic weaknesses, positional imbalances.
Background usually holds the most signals and the least urgent ones, so it is collapsed by default. During play, leave it closed and act on the sections above. When the position is quiet — no checks, threats, or opportunities demanding attention — open Background to see whether a slower, positional idea is worth pursuing. (Compare follows the same rule: while Background is collapsed it hides Background-only changes.)
Amber squares mark the from/to squares of the last move.
Hover over a signal to flash the board squares it refers to; click the signal to flash them again, or click a single square reference to flash just that one. There's a brief pause before a hover flashes, so sweeping the mouse across the list doesn't set everything flashing at once.
The Library tab displays the currently open library. Use the Open ▾ (or library-name ▾) menu to open, create, import, switch, or reopen a recent library, or to clear one of your own writable libraries (emptying the file but leaving it on disk); search and browse games; and select a game to analyse. Library games are treated as reference material and remain unchanged.
Workspace is your personal analysis area — everything here is editable and saved automatically.
Workspace games can be created by creating a new game, building a position, loading a PGN or FEN, or analysing a library game and entering a new move. When you make a move in a library game, ChessSignals automatically creates a Workspace copy so you can explore ideas without modifying the original.
Library games can be viewed in two modes.
Normal viewing mode — full move list visible, free navigation, Signals update normally.
A training mode for learning from master games. Switch a library game between Study and Predict using the buttons at the top of the Library tab.
On the board, the reveal shows both moves at once: the game move in amber, your move in magenta.
The Compare tab (top right) shows how the two moves differ in signals — what the game move offers that yours does not, what yours offers, and where the same square reads differently.
Leave Predict mode at any time with the Back to Study button in the Signals panel, or by pressing Esc.
Use the replay control beneath the board to play through a game automatically. Controls: Play, Pause, Stop, and adjustable replay speed. Replay stops automatically if you manually navigate or interact with the board.
ChessSignals can reduce the visibility of pieces while leaving pawns fully visible. This helps you focus on the pawn structure, which often determines the strategic character of a position.
The opacity slider in the 🎨 panel controls how strongly pieces are faded: 100% is a normal board, 50% keeps pieces visible but less prominent, 0% shows pawns only.
Tap the ℹ️ button next to the slider for a full guide to using this feature.
Experimental. Start a game against the computer with "Play Engine as White" or "Play Engine as Black" in the Workspace + New menu (or the Engine button on an engine game).
You can also play the engine on from any existing Workspace game — a built position, a loaded FEN or PGN, or an analysis you are continuing — with the Play Engine button in the Workspace toolbar. It takes over the side you are not playing and replies from the current position.
The engine is deliberately not a conventional engine like Stockfish. It uses no deep search, no opening book, and no neural network. It looks just one move ahead and scores each option from the same signals you see in the panel, together with a few general chess principles — take the centre, develop your pieces, castle for safety, keep knights off the rim, centralise the king in the endgame, avoid leaving pieces hanging, and prefer forks, pins and pressure.
It exists for two reasons: to see how far you can get with signals and principles alone — a modest engine that can explain every move in plain English — and to give you a hands-on way to explore the signal system by playing real games.
Its play is weak and it will blunder. That is part of the experiment, not a finished product.
Mobility is a count of legal moves available to each side in the current position.
A piece that has more squares it can safely reach is more active. A piece that is blocked, pinned, or cramped contributes less to your game.
ChessSignals counts every legal move for each side and compares them.
When one side has significantly more moves than the other, a signal appears in the Background section:
You have more moves (30 to their 28, giving a ratio of 1.07)
The ratio is simply your move count divided by theirs. A ratio above 1.0 means you are more mobile; below 1.0 means they are.
Each player's row shows that side's mobility ratio as a small number (e.g. 1.07) to the left of their captured pieces. It is colour-graded so you can read the balance at a glance:
The two numbers are reciprocals of each other (if one side reads 1.20, the other reads 0.83). The number only appears after the tenth move, once the opening is over and mobility differences start to mean something — the same point at which the "stuck piece" markers begin to show.
A side with more mobile pieces has more options: more squares to threaten, more ways to regroup, more flexibility to respond to threats.
Restricted mobility is often a sign of positional danger even when no piece is directly attacked. Cramped pieces limit your choices — and limited choices mean mistakes become more likely.
Alexander Shashin, in his book Best Play: A New Method for Discovering the Strongest Move, proposed a practical framework for deciding how to approach a position.
His insight was that the character of the best play changes depending on the balance of mobility, material, king safety, and other factors. He identified three zones, which you can read straight from the mobility ratio shown in the Background signals:
Petrosian zone — mobility ratio below 0.75
You have significantly fewer moves than your opponent. The priority is defence: consolidate, reduce weaknesses, and avoid commitments that could be exploited. Named after Tigran Petrosian, whose style was built on restriction and prophylaxis.
Capablanca zone — mobility ratio between 0.75 and 1.25
Mobility is roughly balanced. Sharp tactics are less likely to succeed for either side. The right approach is quiet manoeuvring: improve your pieces, restrict theirs, and wait for a genuine imbalance to appear. Named after José Raúl Capablanca, whose play was characterised by clear, efficient technique.
Tal zone — mobility ratio above 1.25
You have significantly more moves than your opponent. Your pieces are active and their position is cramped. This is the moment to create complications, open lines, and press for a decision. Named after Mikhail Tal, the Latvian attacking genius known for his sacrifices and combinative play.
Shashin designed this framework for human players, not engines. Engines evaluate millions of positions; humans cannot. The zone framework gives you a practical question to ask before choosing a plan: am I in the Petrosian, Capablanca, or Tal zone right now?
ChessSignals is designed to answer three questions:
The aim is not to replace calculation. The aim is to help you see the important features of the position more quickly and more consistently.
Copyright © 2026 Philip White. All rights reserved.
ChessSignals is built on the open-source libraries below. Their copyright and licence notices are reproduced as required.
The analysis engine (geometrics.js) is a modified fork of chess.js 0.10.2.
Copyright (c) 2016, Jeff Hlywa (jhlywa@gmail.com) All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The following components are used under the MIT Licence:
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Download a player's games from Chess.com or Lichess into a new library.
ChessSignals can reduce the visibility of pieces while leaving pawns fully visible. The opacity slider controls how strongly pieces are faded: 100% is a normal board, 50% keeps pieces visible but less prominent, 0% shows pawns only.
Many important strategic features are easier to see when the pieces are less distracting:
These features often remain hidden when the eye is drawn to tactical piece activity.
Strong players frequently begin their positional assessment by examining the pawn structure. Reducing piece visibility makes these patterns much easier to recognise. Questions to ask:
Reduce piece opacity to identify typical pawn structures, long-term plans, and common pawn breaks.
Use low opacity to locate weak pawns, space advantages, potential outposts, and attacking directions.
Pawns often become the most important factor. Low opacity highlights passed pawns, pawn races, majorities, and promotion threats.
Try moving the slider to zero and looking only at the pawns. Before restoring the pieces, ask yourself: who has more space? Where are the weaknesses? Which pawn breaks matter? Where should each side play? Then restore the pieces and see how well your assessment matches the complete position.