Ultra C
The term Ultra C is a cultural idiom in Japan that started as the informal strategy used by the Japanese Olympic gymnastics team in 1968. In the 1968 Summer Olympics, gymnastic feats were assigned a difficulty rating A-C, with A being easier than C. Since then, the difficulty ratings have expanded to A-G. At the time, the Japanese team used the term "ultra-C" to describe their strategy, as a metaphor for their goal to perform on a level beyond the best score, or to give "110%". This strategy ultimately brought them the gold medal that year, and the term stuck so well it entered the Japanese lexicon.
Cultural references
Dictionary definition
ウルトラC (Noun) 1. amazing feat; trump card; (something) earth-shattering. Colloquialism, Wasei, originated in Japan, during the 1968 Summer Olympics. From English “ultra C”, C level having been the highest degree of difficulty in artistic gymnastics when the term was coined.