The death of Bobby Fischer in January 2008 brought chess into the headlines, but not this adjective pertaining to chess, which remains as rare as it ever has been.
The main claim to fame of scacchic is that it’s the shortest word in English that contains four letter cs (the longest is floccinaucinihilipilification). The record is held by pneumonoultramicroscopicsilicovolcanoconiosis with six cs.
It, scacchic that is, seems to have been coined in 1860 by a man named Fiske from the Italian word for chess, scacchi. He wrote in his Chess Tales: “Stern old fellows were these scacchic sages! They considered the laws of chess as inviolable as those of the Medes and Persians.”
It’s almost never seen anywhere, except as an occasional obscure reference or witticism in chess magazines. One rare appearance was in 1968, when it briefly appeared in the title of the Central California Chess Association’s journal, The Scacchic Voice.