Sealed Move

Seal arrives in English c. 1200 from Old French seel/seal, ultimately from Latin sigillum — extended senses come via the notion of a seal used to mark and close a document to insure its secrecy, exactly the function of the chess envelope. The practice solved an unfairness of adjournment: the player who moved last would otherwise be at a disadvantage, since the opponent would have a long period to analyze before replying. The solution was to write the last move on paper which the referee seals in an envelope and keeps safe. Sealed moves were already routine in top-level play by the 1920s: Edward Winter's Rubinstein material discusses a sealed move at Budapest 1926 and quotes the 1922 London Rules. No source consulted states exactly when the sealed move was first used.

First documented: 1922 — 1922 London Rules provision for the written adjourned move, cited via Edward Winter's Rubinstein research; confirmed in use at Budapest 1926