lichess.org
Donate

Feedback wanted: a free, engine-verified reference of chess tactics

twitter_banner_A_typo.png

Hi everyone,

I'm a Lichess user and an independent developer. I've been building ChessGrammar (https://chessgrammar.com), a free reference of chess tactical motifs: no account, no ads, no paywall. It's a project I build in the same spirit I like about Lichess.

The idea is to treat tactics like a grammar. Each motif (fork, pin, skewer, discovered attack, deflection, double check, overloading...) gets a precise definition and is split into named variants. Every example position is generated and verified by an engine I wrote for this purpose (Lector64), so each example is guaranteed to actually work.

Currently: 15 motifs, 123 variants, a glossary and a methodology page. Still a work in progress.

I'd really value your opinion:

Do the definitions match how you understand these tactics?
Any variant you think is misclassified or missing?
What would make it more useful for your training?

All criticism welcome. Thanks for reading!

![twitter_banner_A_typo.png](https://image.lichess1.org/display?fmt=png&h=0&op=resize&path=qxoJf_wKviDI.png&w=864&sig=b39bdd3b0db11559bc7e488043f92360cb13bb68) Hi everyone, I'm a Lichess user and an independent developer. I've been building ChessGrammar (https://chessgrammar.com), a free reference of chess tactical motifs: no account, no ads, no paywall. It's a project I build in the same spirit I like about Lichess. The idea is to treat tactics like a grammar. Each motif (fork, pin, skewer, discovered attack, deflection, double check, overloading...) gets a precise definition and is split into named variants. Every example position is generated and verified by an engine I wrote for this purpose (Lector64), so each example is guaranteed to actually work. Currently: 15 motifs, 123 variants, a glossary and a methodology page. Still a work in progress. I'd really value your opinion: Do the definitions match how you understand these tactics? Any variant you think is misclassified or missing? What would make it more useful for your training? All criticism welcome. Thanks for reading!
<Comment deleted by user>

@Bishop1964

so ChessGrammar is a reference site only, it doesn't hold any database, it references the output of chess engine Lector64. Lector64.com is not yet opened to the public, I'm busy building the website, the engine is able to analyze a game and create puzzles on the fly from the tactics that were missed, work in progress!

@Bishop1964 so ChessGrammar is a reference site only, it doesn't hold any database, it references the output of chess engine Lector64. Lector64.com is not yet opened to the public, I'm busy building the website, the engine is able to analyze a game and create puzzles on the fly from the tactics that were missed, work in progress!

@TheDifferenceOfTier5 said ^

You didn’t build anything

lector64.com is opening soon. Chessgrammar is merely its reference. I'm asking here if players think the references are correct in their views, so I can adjust the engine while it is still in beta.

@TheDifferenceOfTier5 said [^](/forum/redirect/post/BHtyfqYX) > You didn’t build anything lector64.com is opening soon. Chessgrammar is merely its reference. I'm asking here if players think the references are correct in their views, so I can adjust the engine while it is still in beta.

I guess the complete page of terms is in the glossary?

Verification and certification:

Best defence - The strongest opposing reply within the scope declared by the verification.

This is basically "best move". (It's actually quite hard to define defense since offense can be defense, but in general the goal of a defensive move is prophylaxis / preventing your opponent from doing something. Since "best move" doesn't exist in verification and certification I assume this is supposed to be best move/best response instead of best defense)

Oh wait, in the context of "goal" the term "best defence" makes sense.

Verification - Control of the claim through a procedure capable of contradicting the detection.

Unclear so: "To perform a procedure capable of showing that a claim is either contradicted or certified."


Chess:

Capture - A move that removes an opponent’s piece from the board by landing on its square.

En passant is a capture

Check - A position in which the side to move’s king is attacked.

A move is called a "check" if it attacks the opponent's king.

A king is "in check" when it is attacked.

Diagonal - A line of squares of one colour running at an angle across the board.

FIDE laws of chess is more precise:

image.png

Draw - A game that ends without a winner.

Technically there are some over-the-board games (and even online daily chess games) which were ruled as 0-0 i.e. both players lost. Which is not really a draw. This definition is perfectly fine imo, but technically the true definition is: "stalemate, insufficient material or dead position, agreement, timeout vs insufficient material or dead position, repetition, fifty or seventy-five move rule"

Gain - The material a side ends up ahead after the sequence under study, against the opponent’s best defence.

Looks like best defence is in two categories.

Screen - A piece standing on a line between a long-range attacker and another piece further along that line.

I haven't heard of that personally. Relevant but different concepts are x-ray and interference.

Sequence - The moves played from the position shown, by both sides in turn, that a claim is read over.

(Also see combination) Note that a puzzle often involves more than one line, so this seems to not work

Tactic - A short forcing operation that gains material or mates, resolved within a few moves against best defence.

Especially with pawn endgames, a tactic just has to end up in a winning position. So actually gaining material or checkmate make take ages under best defense even though it's clearly just winning.

I guess the complete page of terms is in the glossary? Verification and certification: > Best defence - The strongest opposing reply within the scope declared by the verification. This is basically "best move". (It's actually quite hard to define defense since offense can be defense, but in general the goal of a defensive move is prophylaxis / preventing your opponent from doing something. Since "best move" doesn't exist in verification and certification I assume this is supposed to be best move/best response instead of best defense) Oh wait, in the context of "goal" the term "best defence" makes sense. > Verification - Control of the claim through a procedure capable of contradicting the detection. Unclear so: "To perform a procedure capable of showing that a claim is either contradicted or certified." --- Chess: > Capture - A move that removes an opponent’s piece from the board by landing on its square. En passant is a capture > Check - A position in which the side to move’s king is attacked. A move is called a "check" if it attacks the opponent's king. A king is "in check" when it is attacked. > Diagonal - A line of squares of one colour running at an angle across the board. FIDE laws of chess is more precise: ![image.png](https://image.lichess1.org/display?op=noop&path=7Cq_5b_Mlr8y.png&sig=5348a3d4837c4223d32e51cf2291fa56bd2e4354) > Draw - A game that ends without a winner. Technically there are some over-the-board games (and even online daily chess games) which were ruled as 0-0 i.e. both players lost. Which is not really a draw. This definition is perfectly fine imo, but technically the true definition is: "stalemate, insufficient material or dead position, agreement, timeout vs insufficient material or dead position, repetition, fifty or seventy-five move rule" > Gain - The material a side ends up ahead after the sequence under study, against the opponent’s best defence. Looks like best defence is in two categories. > Screen - A piece standing on a line between a long-range attacker and another piece further along that line. I haven't heard of that personally. Relevant but different concepts are x-ray and interference. > Sequence - The moves played from the position shown, by both sides in turn, that a claim is read over. (Also see combination) Note that a puzzle often involves more than one line, so this seems to not work > Tactic - A short forcing operation that gains material or mates, resolved within a few moves against best defence. Especially with pawn endgames, a tactic just has to end up in a winning position. So actually gaining material or checkmate make take ages under best defense even though it's clearly just winning.
<Comment deleted by user>

@sjvv said ^

You didn’t build anything

lector64.com is opening soon. Chessgrammar is merely its reference. I'm asking here if players think the references are correct in their views, so I can adjust the engine while it is still in beta.

I don't see what that has to do with what i said

@sjvv said [^](/forum/redirect/post/SKToBLCh) > > You didn’t build anything > > lector64.com is opening soon. Chessgrammar is merely its reference. I'm asking here if players think the references are correct in their views, so I can adjust the engine while it is still in beta. I don't see what that has to do with what i said

First impressions, I see it as a dictionary with examples - not a bad thing. Could be really useful if organized as training material. Would like to see it expand to cover concepts, e.g. bishop pair, open file...

First impressions, I see it as a dictionary with examples - not a bad thing. Could be really useful if organized as training material. Would like to see it expand to cover concepts, e.g. bishop pair, open file...