Quick answer
Candidate Move Tracker is a practical chess tool: Candidate Move Tracker input/output contract. Work from the first evidence position for Candidate Move Tracker, and begin by testing Kxe8.
Begin from Kxe8 in 3kR3/8/8/8/8/8/8/4K3 b - - 3 2. State the input contract, output assumptions, edge cases and human decision that follows the tool response. The evidence answer is: Candidate Move Tracker: state the input, expected output and the edge case before trusting the tool. Candidate line: Kxe8.
In the Candidate Move Tracker example, notice: side Black; pieces Black king d8, White rook e8, White king e1; legal first moves Kxe8, Kd7, Kc7. Anchor your reading to the FEN above; the inventory is illustrative, not a portable law of chess.
Input and output contract
The first evidence board tests Candidate Move Tracker input/output contract; the second board tests Candidate Move Tracker input/output contract. Where the evidence stores a move string, A is built with direct FEN setup and B with direct FEN setup. Related definitions sit in the Chess Wiki and the Notation And Tools hub. Then compare Fen Viewer with Move List Comparison, Tournament Time Control Planner, Fen Position Editor around the output's hidden assumptions.
The two inventories make the distinction concrete. A contains side Black; pieces Black king d8, White rook e8, White king e1; legal first moves Kxe8, Kd7, Kc7; B contains side Black; pieces Black king d8, White rook e8, White king e1; legal first moves Kxe8, Kd7, Kc7. Compare the side to move before comparing the labels in the context of error feedback a player can act on.
Topic dossier for this page and board pair r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 / r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3: start with the output's hidden assumptions; then test error feedback a player can act on; keep a reproducible setting separate from the check that prevents silent corruption; use the saved position as a baseline as the transfer check; and reserve the limit of automation for the exception.
Human decision after the result
On the first board, calculate Kxe8 after Kxe8 and write down the opponent's best reply around the output's hidden assumptions. On the second board, calculate Kxe8 after Kxe8 and check error feedback a player can act on. 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 the limit of automation.
Key claim: Candidate Move Tracker is illustrated here by Candidate Move Tracker input/output contract; the first concrete test is Kxe8. The board anchor is 3kR3/8/8/8/8/8/8/4K3; 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 candidate move tracker with valid inputs, meaningful outputs, and a safe fallback when the tool is uncertain?”, compare the recorded setup with Kxe8 and the opponent's reply. The decision is useful only when the stated condition survives that concrete test on board 3kR3/8/8/8/8/8/8/4K3. 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 r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3. The false-positive test is whether a reproducible setting appears without the check that prevents silent corruption, so the conclusion is useful only when the stated condition survives that concrete test.
Evidence positions
example-1: Candidate Move Tracker input/output contract
Show answer
Candidate Move Tracker: state the input, expected output and the edge case before trusting the tool. Candidate line: Kxe8.
Why this position is here: Candidate Move Tracker is represented by Candidate Move Tracker input/output contract. This is a direct FEN setup with board anchor 3kR3/8/8/8/8/8/8/4K3; no opening history is inferred from the diagram.
FEN: 3kR3/8/8/8/8/8/8/4K3 b - - 3 2
Question: What is the first concrete decision in this candidate move tracker position?
Answer cue: Candidate Move Tracker: state the input, expected output and the edge case before trusting the tool. Candidate line: Kxe8. The first candidate to test is Kxe8. Replay Kxe8 on board anchor 3kR3/8/8/8/8/8/8/4K3 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 Kxe8, source pgn-specification. This is a direct FEN setup with board anchor 3kR3/8/8/8/8/8/8/4K3; no opening history is inferred from the diagram. If A does not expose Candidate Move Tracker input/output contract, correct the evidence before relying on the prose.
Read the second example (id example-1) separately: continuation Kxe8, source pgn-specification. Its feature is Candidate Move Tracker input/output contract; inventory side Black; pieces Black king d8, White rook e8, White king e1; legal first moves Kxe8, Kd7, Kc7. Compare what changes between Kxe8 and Kxe8.
Failure modes
The main mistake to avoid with Candidate Move Tracker 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 r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 after Kxe8; in B, test it against r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 after Kxe8.
For Candidate Move Tracker, the first board's evidence boundary (after Kxe8) 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 Candidate Move Tracker 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 the saved position as a baseline, 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 r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3; record two candidates, the reply to Kxe8 and the correction. Repeat with B's side to move and r1:3kR3 | r2:8 | 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 Move List Comparison, Tournament Time Control Planner, Fen Position Editor through the check that prevents silent corruption. Keep A's rejected alternative beside B's chosen line Kxe8; this shows whether the conclusion survived a new board signature.
Sources and scope
Sources for Candidate Move Tracker: 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 r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3 / r1:3kR3 | r2:8 | r3:8 | r4:8 | r5:8 | r6:8 | r7:8 | r8:4K3: this page does not claim that Kxe8 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 a reproducible setting.