The long algebraic notation (lan) for null move is usually 00-00 or simply 0000. Chess engines that support the nullmove: "give up a turn, and let the other side move" typically use this as its part of UCI. What would the SAN representation be?

  • Actually, I'm not even aware there is such thing as nullmove in SAN. But I could be wrong.
    – SmallChess
    Apr 2, 2016 at 23:16
  • I'm guessing 00 similar to pawn move d4 Apr 3, 2016 at 0:41

1 Answer 1


Νικόλαος Μανωλακος asked:

What would the SAN representation [of a null move] be?

Several possibilities present themselves as to what the SAN notation can be, but none that I have found claim to be the official standard specification for SAN. The following results indicate within the quotation marks the annotation used (intended to be used without the quotation marks).

NAG (Numeric Annotation Glyph) "$0"
     IAW art. 10, table 1, line 1 [ref. 1, 2, 3]

PGN's SAN:  "--"
     [ref. 4, 5, 6, 7]
     Note:  In ref. 7, null moves start out as mere comments, and can become [null] moves, but it's unclear as to whether they necessarily become so.

PGN's SAN:  "@@@@"
     [ref. 8]

"<>", "--"
     [ref. 9]
     Note:  "A Null Move acts as a placeholder for an expected move that is not played."

"pass", "null", "@@@@"
     [ref. 10]

Stockfish's SAN:  "null"
     [ref. 11]

     [ref. 12]


  1. http://www.saremba.de/chessgml/standards/pgn/pgn-complete.htm#c10
  2. https://www.chessclub.com/user/help/PGN-spec
  3. https://metacpan.org/pod/distribution/Games-Chess/lib/Games/Chess/PGN.pod#NUMERIC-ANNOTATION-GLYPHS
  4. https://github.com/k2052/chess.rb/blob/master/lib/chess/san.rb
  5. https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/help.html#portability
  6. https://www.gnu.org/software/xboard/whats_new/4.6.0/#tag-D6
  7. http://www.triplehappy.com/faq.html
  8. https://www.gnu.org/software/xboard/engine-intf.html#8
  9. http://www.enpassant.dk/chess/palview/manual/pgn.htm#pgncontnull
  10. http://hgm.nubati.net/alien.html
  11. https://github.com/mcostalba/FishCooking/blob/master/src/notation.cpp
  12. https://github.com/erashid/DON/blob/master/src/Notation.cpp

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