Quick answer
Increment Choice Guide is a practical chess tool: Increment Choice Guide input/output contract. Work from the first evidence position for Increment Choice Guide, and begin by testing Re8+.
Begin from Re8+ in 5k2/4R3/8/8/8/8/8/4K3 w - - 2 2. State the input contract, output assumptions, edge cases and human decision that follows the tool response. The evidence answer is: Increment Choice Guide: state the input, expected output and the edge case before trusting the tool. Candidate line: Re8+.
In the Increment Choice Guide example, notice: side White; pieces Black king f8, White rook e7, White king e1; legal first moves Re8+, Rf7+, Rg7, Rh7, Re6, Re5, Re4, Re3. Use the inventory as a reading aid for this position alone rather than as a template for other games.
Input and output contract
The first evidence board tests Increment Choice Guide input/output contract; the second board tests Increment Choice Guide input/output contract. A is seeded by the moves direct FEN setup. B is seeded by direct FEN setup. Shared language is catalogued on the Chess Wiki and the Notation And Tools hub. Then compare Fen Viewer with Chess Clock Time Control Builder, Expected Score Calculator, Performance Rating Explanation around the decision after the tool responds.
The two inventories make the distinction concrete. A contains side White; pieces Black king f8, White rook e7, White king e1; legal first moves Re8+, Rf7+, Rg7, Rh7, Re6, Re5, Re4, Re3; B contains side White; pieces Black king f8, White rook e7, White king e1; legal first moves Re8+, Rf7+, Rg7, Rh7, Re6, Re5, Re4, Re3. Compare the side to move before comparing the labels in the context of a deliberately bad input.
Topic dossier for this page and board pair r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 / r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3: start with the decision after the tool responds; then test a deliberately bad input; keep the field that must be preserved separate from side-to-move interpretation; use a repeatable workflow as the transfer check; and reserve a comparison with a known result for the exception.
Human decision after the result
On the first board, calculate Re8+ after Re8+ and write down the opponent's best reply around the decision after the tool responds. On the second board, calculate Re8+ after Re8+ and check a deliberately bad input. Use the tool to expose a position or comparison, then audit the input and decide what the output does and does not establish. In this case the useful condition is a comparison with a known result.
Key claim: Increment Choice Guide is illustrated here by Increment Choice Guide input/output contract; the first concrete test is Re8+. The board anchor is 5k2/4R3/8/8/8/8/8/4K3; the example is intentionally narrower than the topic label and should not be generalised without checking the surrounding position..
Practical boundary: To answer “How can a player use increment choice guide with valid inputs, meaningful outputs, and a safe fallback when the tool is uncertain?”, compare the recorded setup with Re8+ and the opponent's reply. The decision is useful only when the stated condition survives that concrete test on board 5k2/4R3/8/8/8/8/8/4K3. The evidence records Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position and the second board signature r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3. The false-positive test is whether the field that must be preserved appears without side-to-move interpretation, so the conclusion is useful only when the stated condition survives that concrete test.
Evidence positions
example-1: Increment Choice Guide input/output contract
Show answer
Increment Choice Guide: state the input, expected output and the edge case before trusting the tool. Candidate line: Re8+.
Why this position is here: Increment Choice Guide is represented by Increment Choice Guide input/output contract. This is a direct FEN setup with board anchor 5k2/4R3/8/8/8/8/8/4K3; no opening history is inferred from the diagram.
FEN: 5k2/4R3/8/8/8/8/8/4K3 w - - 2 2
Question: What is the first concrete decision in this increment choice guide position?
Answer cue: Increment Choice Guide: state the input, expected output and the edge case before trusting the tool. Candidate line: Re8+. The first candidate to test is Re8+. Replay Re8+ on board anchor 5k2/4R3/8/8/8/8/8/4K3 and write down what changes after it.
Evidence boundary: Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position.
Reading the test case
Read the first example (id example-1) as a complete record: continuation Re8+, source pgn-specification. This is a direct FEN setup with board anchor 5k2/4R3/8/8/8/8/8/4K3; no opening history is inferred from the diagram. If A does not expose Increment Choice Guide input/output contract, correct the evidence before relying on the prose.
Read the second example (id example-1) separately: continuation Re8+, source pgn-specification. Its feature is Increment Choice Guide input/output contract; inventory side White; pieces Black king f8, White rook e7, White king e1; legal first moves Re8+, Rf7+, Rg7, Rh7, Re6, Re5, Re4, Re3. Compare what changes between Re8+ and Re8+.
Failure modes
The main mistake to avoid with Increment Choice Guide is trusting a convenient output without checking the position, input format or limitations hidden by the interface. In A, the missing condition must be located in r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 after Re8+; in B, test it against r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 after Re8+.
For Increment Choice Guide, the first board's evidence boundary (after Re8+) is Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position. The second board's evidence boundary for Increment Choice Guide is Illustrative evidence for the stated mechanism; it is not a claim that the candidate move is forced or best in every position. If a trusted source or careful calculation changes the conclusion around a repeatable workflow, update both the evidence record and this article.
Practice protocol
run the workflow on a known position, one edge case and one invalid input; save the result and the reason for each outcome. Start with A's side to move and r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3; record two candidates, the reply to Re8+ and the correction. Repeat with B's side to move and r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3; the changed board tests transfer rather than diagram memory.
After the drill, compare your notes with Chess Clock Time Control Builder, Expected Score Calculator, Performance Rating Explanation through side-to-move interpretation. Keep A's rejected alternative beside B's chosen line Re8+; this shows whether the conclusion survived a new board signature.
Sources and scope
Sources for Increment Choice Guide: 1chess.online editorial scope, Portable Game Notation Specification. Source ids are original-analysis, pgn-specification. Primary evidence hook: pgn-specification. Comparisons and practice notes are editorial. Evidence revision: 2026-08-remediation-r2.
Scope note for board pair r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 / r1:5k2 | r2:4R3 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3: this page does not claim that Re8+ is an engine principal variation, that an exact endgame result is verified when the evidence says it is not, or that a tool output replaces human calculation. The conclusion is limited to the recorded boundary and the exception the field that must be preserved.