Board vision · unit 3 of 4

Counting attackers

How many pieces hit a square — fast enough that the answer arrives before you have finished asking.

Not started

clean = right, and inside the cap

What this unit is for

Every question in the seeds course reduces to this one. Is that piece loose? is "zero defenders." Is it underguarded? is "more attackers than defenders." If counting is slow or wrong, everything built on top inherits the error and you never find out where it came from.

So the target is not accuracy. It is accuracy under a clock. Counting correctly in forty seconds is not board vision — in a real game that budget is already spent on something else.

Not in this unit

Whether a capture is good. Counting comes first; evaluating exchanges is unit 4.
Tactics, motifs, or seeds. Those need this unit finished.
Legality. A pinned piece still attacks what it attacks.

Block 1Read · ~8 min

Three rules, and the third is the one that costs people

Rule 1A piece attacks a square if it could capture there — regardless of what is standing on it, and regardless of whether the move would be legal. Pawns attack diagonally forward only, never the square straight ahead. A king attacks all eight neighbours but never the square it stands on.
Rule 2A queen, rook or bishop stops at the first piece in the way. If anything at all sits between it and the square, it does not attack that square.
Rule 3Unless that piece is one of yours that attacks the same square. Then both count: a rook behind a rook on an open file, a queen behind a bishop on a diagonal. This is a battery, and the piece behind is an x-ray attacker.

Why rule 3 is not a technicality

When the front piece captures, the back one recaptures. So for every purpose that matters — whether a square is safe, whether a defender is enough — the back piece was always part of the count. People who stop at rule 2 systematically undercount exactly the squares where the fight is real.

One vocabulary note that saves confusion later. Counting your own pieces that attack a square is the same operation as counting the enemy's; it just has a different name. Attacking your own square is defending it.

Block 2Do · ~20 min

Practice — ten positions, with the answer shown

The clock runs but nothing is at stake here. Feedback is full at first and thins out as you go, so by the last three you are getting the count and nothing else.

Block 3Do · ~12 min

The check — twenty positions you have not seen

Drawn fresh from a held-out pool, so a retake is a new set rather than a memory test. No feedback until the end.

The gate is 18 of 20, each inside its cap. Two misses is not generosity — it is the width of a bad day. A third means the rule has not automated yet, which is a reason to keep drilling and not a verdict about you.

Block 4Ask · open-ended

The misses are the useful part

Flag anything you got wrong, or got right and did not trust. The button below assembles every flagged item into one block of text — position, question, right answer, your answer, your note — and copies it. Paste it into the tutor project and argue about it.

Ask for the rule, not the answer

You already have the answer; it is in the packet. The question worth asking is which of the three rules you applied wrongly, and whether the mistake was the rule or the reading. Those need opposite fixes — a misremembered rule gets restated, a misread board gets drilled.