Build a Woodpecker Set From Your Own Positions

The Woodpecker Method is simple. You take a set of tactical positions and cycle through it in timed rounds, and each pass is faster than the last, until the patterns are automatic instead of calculated. Until now you drilled the curated sets we built. Now you can build the set from your own material: a coach's FEN handout, an annotated PGN, or your own analyzed games.

There is a new "Import positions" button on the Woodpecker page. That is the whole entry point.

How it works

You give it positions two ways. Paste FENs, one per line, straight into the box. Or upload a file, a PDF, a PGN, or a plain .txt.

From a file, it pulls positions three ways.

First, literal FENs. If the text has FEN strings in it, like an exercise sheet or a database export, it reads them directly.

Second, annotated games. If you upload a game score with the author's marks, it replays the game from move one and harvests the moments the author flagged. Before a move marked "!", so the puzzle is finding the strong move. After a move marked "??", so the puzzle is punishing the mistake. It is using the book's own tactical curriculum, the moves someone already decided were worth pointing at.

Third, raw unannotated games. If there are no marks, it runs its own engine scan over the games and finds the spots where the evaluation fell off a cliff.

Every position gets checked

Here is the part that matters. However a position gets in, it does not become a puzzle just because it showed up. Stockfish checks every candidate, and a position only survives if a single move clearly dominates: a forced mate, or a winning move that is clearly better than the second best. If two moves are roughly as good, or the position is quiet and equal, it gets thrown out.

That is on purpose. A Woodpecker set trains recognition, and "find the move" only works if there is one honest answer. Mushy positions where three moves are fine teach you nothing, so they do not make the cut. You end up with a clean set where every position has a real, single solution.

The result is a normal frozen Woodpecker set. It locks at creation and you cycle it in timed rounds, exactly like the built-in sets, each round faster than the last.

What it is actually good for

The obvious use is a coach's handout. If someone gave you 40 positions to work on, paste the FENs and drill them properly instead of clicking through once and forgetting them.

The second is an annotated game collection. A well-annotated PGN is a tactics course its author already built. Now you can cycle it.

The third is your own analyzed games. Run your games through analysis, export them, and the engine scan pulls the mistakes worth burning into memory.

The honest limits

A few things it does not do, so you are not surprised.

It reads the text layer of a PDF, not the diagrams. If your book is a scanned image, there is no text to read and it will find nothing. It needs actual FEN strings or move text in the file.

It works best for tactical material. A quiet opening position has no single best move to check against, so it gets filtered out. Feed it tactics, not theory.

Unannotated games are the weakest input. The engine scan finds mistakes, but the yield is modest, and only the ones with a single clear punishment survive the gate. An annotated file or a FEN sheet will always give you more.

On the free tier you get one custom set and five imports a day, and it is not behind the paywall. You can build a real set from your own positions for free.