Quick answer
Vancura Defense is an endgame technique: Lucena bridge-building. Work from the first evidence position for Vancura Defense, and begin by testing Kc5.
Begin from Kc5 in 2R5/6kr/2K5/8/8/8/8/R7 w - - 1 2. Count the material, king routes, promotion squares and reserve tempi before applying a theoretical rule. The evidence answer is: Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: Kc5.
In the Vancura Defense example, notice: side White; pieces White rook c8, Black king g7, Black rook h7, White king c6, White rook a1; legal first moves Rd8, Re8, Rf8, Rg8+, Rh8, Rc7+, Rb8, Rca8. The side-to-move and piece list are scoped to this teaching position and stop there.
Material and result question
The first evidence board tests Lucena bridge-building; the second board tests Lucena bridge-building. A opens with the string direct FEN setup, whereas B opens with direct FEN setup. Look up neighbouring ideas via the Chess Wiki and the Endgames hub. Then compare Material Values with Philidor Position, Rook And Pawn On The Sixth Rank, Rook Endgame Bridge Building around the defender's fortress setup.
The two inventories make the distinction concrete. A contains side White; pieces White rook c8, Black king g7, Black rook h7, White king c6, White rook a1; legal first moves Rd8, Re8, Rf8, Rg8+, Rh8, Rc7+, Rb8, Rca8; B contains side White; pieces Black king h8, White pawn c7, White king b5, Black rook d5, White rook e1; legal first moves Ka6, Kb6, Kc6, Kc4, Kb4, Ka4. Compare the side to move before comparing the labels in the context of the pawn's promotion square.
Topic dossier for this page and board pair r1:2R5 | r2:6kr | r3:2K5 | r4:8 | r5:8 | r6:8 | r7:8 | r8:R7 / r1:7k | r2:2P5 | r3:8 | r4:1K1r4 | r5:8 | r6:8 | r7:8 | r8:4R3: start with the defender's fortress setup; then test the pawn's promotion square; keep the defender's only active counterplay separate from an outside passer used as a decoy; use the conversion move order as the transfer check; and reserve the active rook before the pawn push for the exception.
Conversion or defense plan
On the first board, calculate Kc5 after Kc5 and write down the opponent's best reply around the defender's fortress setup. On the second board, calculate Ka6 after Ka6 and check the pawn's promotion square. Separate the practical conversion question from the result question; side to move and one checking distance can change the conclusion. In this case the useful condition is the active rook before the pawn push.
Key claim: Vancura Defense is illustrated here by Lucena bridge-building; the first concrete test is Kc5. The board anchor is 2R5/6kr/2K5/8/8/8/8/R7; the example is intentionally narrower than the topic label and should not be generalised without checking the surrounding position..
Practical boundary: To answer “What exact king, pawn, and move-order conditions decide vancura defense, and how should each side play them?”, compare the recorded setup with Ka6 and the opponent's reply. The decision is useful only when the stated condition survives that concrete test on board 7k/2P5/8/1K1r4/8/8/8/4R3. The evidence records No tablebase outcome is asserted by this generated record; verify the exact FEN before publication and the second board signature r1:7k | r2:2P5 | r3:8 | r4:1K1r4 | r5:8 | r6:8 | r7:8 | r8:4R3. The false-positive test is whether the defender's only active counterplay appears without an outside passer used as a decoy, so the conclusion is useful only when the stated condition survives that concrete test.
Evidence positions
example-1: Lucena bridge-building
Show answer
Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: Kc5.
Why this position is here: Vancura Defense is represented by Lucena bridge-building. This is a direct FEN setup with board anchor 2R5/6kr/2K5/8/8/8/8/R7; no opening history is inferred from the diagram.
FEN: 2R5/6kr/2K5/8/8/8/8/R7 w - - 1 2
Question: What is the first concrete decision in this vancura defense position?
Answer cue: Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: Kc5. The first candidate to test is Kc5. Replay Kc5 on board anchor 2R5/6kr/2K5/8/8/8/8/R7 and write down what changes after it.
Evidence boundary: No tablebase outcome is asserted by this generated record; verify the exact FEN before publication.
example-2: Lucena bridge-building
Show answer
Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: Ka6.
Why this position is here: Vancura Defense is represented by Lucena bridge-building. This is a direct FEN setup with board anchor 7k/2P5/8/1K1r4/8/8/8/4R3; no opening history is inferred from the diagram.
FEN: 7k/2P5/8/1K1r4/8/8/8/4R3 w - - 4 3
Question: What is the first concrete decision in this vancura defense position?
Answer cue: Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: Ka6. The first candidate to test is Ka6. Replay Ka6 on board anchor 7k/2P5/8/1K1r4/8/8/8/4R3 and write down what changes after it.
Evidence boundary: No tablebase outcome is asserted by this generated record; verify the exact FEN before publication.
example-3: Lucena bridge-building
Show answer
Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: c8=Q.
Why this position is here: Vancura Defense is represented by Lucena bridge-building. This is a direct FEN setup with board anchor 8/2P4k/2K5/6r1/8/8/8/3R4; no opening history is inferred from the diagram.
FEN: 8/2P4k/2K5/6r1/8/8/8/3R4 w - - 6 4
Question: What is the first concrete decision in this vancura defense position?
Answer cue: Vancura Defense: use the king's shelter and a checking-distance bridge before advancing the pawn. Candidate line: c8=Q. The first candidate to test is c8=Q. Replay c8=Q on board anchor 8/2P4k/2K5/6r1/8/8/8/3R4 and write down what changes after it.
Evidence boundary: No tablebase outcome is asserted by this generated record; verify the exact FEN before publication.
Reading the line
Read the first example (id example-1) as a complete record: continuation Kc5, source tablebase. This is a direct FEN setup with board anchor 2R5/6kr/2K5/8/8/8/8/R7; no opening history is inferred from the diagram. If A does not expose Lucena bridge-building, correct the evidence before relying on the prose.
Read the second example (id example-2) separately: continuation Ka6, source tablebase. Its feature is Lucena bridge-building; inventory side White; pieces Black king h8, White pawn c7, White king b5, Black rook d5, White rook e1; legal first moves Ka6, Kb6, Kc6, Kc4, Kb4, Ka4. Compare what changes between Kc5 and Ka6.
Boundary cases
The main mistake to avoid with Vancura Defense is applying a remembered endgame rule while ignoring side to move, king placement or an unverified result. In A, the missing condition must be located in r1:2R5 | r2:6kr | r3:2K5 | r4:8 | r5:8 | r6:8 | r7:8 | r8:R7 after Kc5; in B, test it against r1:7k | r2:2P5 | r3:8 | r4:1K1r4 | r5:8 | r6:8 | r7:8 | r8:4R3 after Ka6.
For Vancura Defense, the first board's evidence boundary (after Kc5) is No tablebase outcome is asserted by this generated record; verify the exact FEN before publication. The second board's evidence boundary for Vancura Defense is No tablebase outcome is asserted by this generated record; verify the exact FEN before publication. If a trusted source or careful calculation changes the conclusion around the conversion move order, update both the evidence record and this article.
Practice from a real game
play the position for both sides, record the critical tempo, and verify the exact FEN against the cited tablebase before publication. Start with A's side to move and r1:2R5 | r2:6kr | r3:2K5 | r4:8 | r5:8 | r6:8 | r7:8 | r8:R7; record two candidates, the reply to Kc5 and the correction. Repeat with B's side to move and r1:7k | r2:2P5 | r3:8 | r4:1K1r4 | r5:8 | r6:8 | r7:8 | r8:4R3; the changed board tests transfer rather than diagram memory.
After the drill, compare your notes with Philidor Position, Rook And Pawn On The Sixth Rank, Rook Endgame Bridge Building through an outside passer used as a decoy. Keep A's rejected alternative beside B's chosen line Ka6; this shows whether the conclusion survived a new board signature.
Sources and scope
Sources for Vancura Defense: Syzygy tablebase verification reference, 1chess.online editorial scope. Source ids are tablebase, original-analysis. Primary evidence hook: tablebase. Comparisons and practice notes are editorial. Evidence revision: 2026-08-remediation-r2.
Scope note for board pair r1:2R5 | r2:6kr | r3:2K5 | r4:8 | r5:8 | r6:8 | r7:8 | r8:R7 / r1:7k | r2:2P5 | r3:8 | r4:1K1r4 | r5:8 | r6:8 | r7:8 | r8:4R3: this page does not claim that Kc5 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 defender's only active counterplay.