Meanings
- uncommonboard gamesOf a chess player: following a main line ("a standard sequence of opening moves considered to be best play").
The Sicilian opening was wild, but the speed of play made it clear both players were "in book", up to a point.
2022 January 21, Colin McGourty, “Tata Steel 5: Rapport & Mamedyarov hit the front”, in chess24, archived from the original on 19 May 20221 more example
Wesley So had prepared a line with a temporary pawn sacrifice against Praggnanandhaa and both players appeared to be in book for a long time.
2023 January 19, Mark Crowther, “Giri overtakes Abdusattorov in a dramatic final round of the Tata Steel Masters to grab his first title”, in The Week in Chess, archived from the original on 01 Feb 2023Antonyms: out of book
Synonyms & antonyms
prepositional phraseOf a chess player: following a main line ("a standard sequence of opening moves considered to be best play").
Cite this entry
in book. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/in%20book
“in book.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/in%20book. Accessed November 4, 2026.
WatkinsX Dictionary, s.v. “in book,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/in%20book.
Source: in book on Wiktionary, CC BY-SA 4.0.