SFEN Collection Viewer

Browse SFEN position collections on a board and import a position

SFEN Format Position Navigation Board Flipping Import to Main Window

Screenshots were captured on Linux with the English interface.

Collection Files

Prepare a text file with one SFEN position per line

1 Writing a Collection File

A collection file is a text file (.sfen or .txt) with one position per line. Empty lines and lines starting with “#” (comments) are ignored, so files saved by the Tsume Position Generator open as they are.

  • SFEN: board, side to move, pieces in hand and move number (the move number may be omitted). The line may start with “sfen ”
  • USI “position sfen …”, “position startpos” and “startpos” (the standard starting position): moves listed after “moves” are played, and the resulting position is used
  • An SFEN followed by “moves” and a sequence (as saved by the Tsume Position Generator with Include moves): the sequence is ignored and the SFEN position is shown

Lines that cannot be read as a position (a malformed board or hand, an illegal move, and so on) are skipped, and the number of skipped lines is shown next to the file name. If the file contains no positions at all, a message appears and the collection already on display stays as it is.

Example: positions.sfen

# Three positions from Suzuki vs Yamada (October 5, 2026)
l5s1l/4k2b1/1rg1pp1gn/3p2p1p/2P4p1/pPGP1P3/Bp2KSP1P/7R1/LNS2G1NL b sn4p 63
6s1l/4k2b1/1r2pp1gn/2Gp2p1p/1PbP3p1/5P3/+lp2gSP1P/7R1/1NSK1G1NL w NPsl5p 78
6s1l/4k4/4pp1gn/2pp2p1p/1BrP3p1/1sP2P3/K1+b1gSP1P/3+l3R1/5G1NL b GSLP2n5p 101

Browsing a Collection

Step through the positions in the viewer

2 Open a Collection

Choose Edit → SFEN Collection Viewer. The viewer is a separate window, so you can keep using the main window while it is open.

Click Open File and choose a collection file; the first position appears on the board. Pieces in hand are shown on the stands, the side to move is marked with the Turn badge on its name, and the line below the board shows which position you are on, such as “Position: 1 / 3”. History opens one of the last five files.

SFEN Collection Viewer

SFEN Collection Viewer: positions.sfen open at position 1 (Black to move)

3 Move Between Positions and Flip the Board

Use First, Previous, Next and Last to move between positions. Flip Board shows the board from White’s side.

Zoom in and Zoom out (or Ctrl + mouse wheel over the board) change the board size, and the window resizes to fit the board. The board size is kept for the next time. A- and A+ at the bottom left change the size of the buttons and text.

SFEN Collection Viewer with the board flipped

Flip Board: position 2 (White to move) seen from White’s side

Importing a Position

Bring the chosen position into the main window

4 Import a Position into the Main Window

Show the position you want and click Select. It becomes the starting position in the main window, and the game record is reduced to that starting position. From there you can start Consideration Mode, or start a game with Current Position as the starting position.

If the main window has an unsaved game record, you are first asked whether to save it. The imported position is treated as a new game record: Save opens Save As instead of overwriting the record file you had open. The viewer stays open, so you can import another position right away.

Main window after importing a position

Main window: position 2 imported as the starting position

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