Calculation TrainingCalculationbeta

The board will not move. Write the whole line, both sides, from the position as it stands — then commit. That is the training.

Writing the line

• Play moves on the board to write them. Click a move you have already written to select it, and what you play next depends on whose turn you clicked: the same side starts a bracket — an alternative to that move — and a reply carries the line on from it.
• ⌫ Delete move removes the selected move and everything after it — on the last move, just that move. Backspace does the same.
• ∅ Clear all throws the whole line away and gives you the empty board back.
• ↑ Promote makes a bracket the main line; ↓ Demote sends the main line into a bracket.
• The panel under the line always points at the selected move — and at the position itself before you have written anything, so what you see in the diagram has somewhere to go.

What scores

• Brackets that answer other defences — the moves your opponent might have played instead. Those are the calculation.
• Assessment is a bet. Get every one right and it pays +1; a single wrong one forfeits the lot.
• Expected is the score your rating predicts on this position. Beat it and the rating climbs.
• Your mark and your note never score. They are yours.

Marks and notes, from the keyboard

• ! and ? cycle the mark on the selected move.
• Any other letter starts a note — the blinking cursor is the invitation, and there is nothing to click. Enter saves it; Enter again commits the line.
• Notes written before you commit are sealed at commit, so they stay a record of what you actually saw rather than what you wish you had.

After you commit

• Clicking a move in your own line steps the board there and puts the cursor in its note. You can post the annotated line to the kibitzers.
• Brackets in the printed solution are the tries that fail — the move most solvers want to play, and its refutation.
• The board steps on click; the left edge goes back.

Hover anything for its meaning.