Which game is a chess variant, Ubongo or Ouk-Khmer?
Ouk-Khmer (Hill's version) Ouk-Khmer (also known as Cambodian Chess) is a chess variant which D. B. Pritchard claimed was played in Cambodia although its actual origins appear to be unknown. Pritchard gives the source as P. A. Hill. It combines elements of makruk and xiangqi. Similar to xiangqi, it is played on the intersections of an 8×8 monotone board (Instead of 8x9). Contrary to Pritchard's claim, the actual variety of chess played in Cambodia today, known as "Ok" or "Ouk Chatrang" is nearly identical to Makruk. The authenticity of the game described by Pritchard remains doubtful.
Tandem simultaneous exhibition A tandem simultaneous exhibition or leapfrog simultaneous exhibition or partnership chess is a form of simultaneous exhibition in which more than one players (typically of high rank, such as a grandmaster or dan-level player) play multiple games at a time with a number of other players, making successive moves without consulting one another. Such an exhibition is often referred to simply as a "tandem simul" or "leapfrog simul". When conducted by more than two experts, it is often called a sequential simul.