- Ultima . Version using Alfaerie graphics. Author: David Howe. Inventor: Robert Abbott.
- Ultima with Alternate Graphics . Game where each type of piece has a different capturing ability. Author: David Howe. Inventor: Robert Abbott.
- Ultimate Battle Chess . Pawns, kings, queens, and knights move differently. By Vu Q Vo.
- Ultimatum . Variant of Ultima that adds a FIDE-Queen and an Advancer in place of one Long-Leaper and one Chameleon. By Roberto Lavieri.
- Ultra Chess. On 10 by 10 board with two queens, and major pieces have an additional king's move. Author: Pavel Tikhomirov. Inventor: Ruggero Micheleto.
- Ultra Slanted Escalator Chess . Game on an asymmetrical board of 84 squares with Crabs and Ultras. Author: Peter Aronson. Inventor: David Short.
- Unconventional Warfare Chess . Variant based on modern warfare. Author: Dan Troyka. Inventor: Luiz Carlos Campos.
- Undecided Chess . Pieces begin in an undecided state until they move. By Adrian Alvarez de la Campa.
- Unicorn Chess . 10x10 variant with a new piece that moves as a Bishop or a Nightrider. Author: Fergus Duniho. Inventor: David Paulowich.
- Unirexal Chess . Only white has a king. Author: Uwe Wiedemann. Inventor: Vernon Rylands Parton.
- Unreal Tournament Chess . Chess variants with a different objective, inspired by the multiplayer computer game Unreal Tournament. Author: Robert Price. Inventor: João Pedro Neto.
- Upside-Down Chess . White starts at the upper two rows, black at the bottom. Author: Marek14 .
|12 'Zillions of Games file' entries listed||4 'Large board' entries listed|
|1 'War game' entry listed||1 'Unorthodox shaped board' entry listed|
|2 'In a category all its own' entries listed||1 'Each player has a different army' entry listed|
Total items listed: 12