General Tchike was part of UNISYC.
He first met the Doctor in 2054 Saskatoon. He referred to the incarnation as "the little baggy one", so it could have been the Second or Seventh Doctor. They fought the Montana Republican Militia, who had obtained thermosystron bombs which they wanted to use to take over Canada. The Doctor destroyed them contrary to Tchike's orders from the World Zones Authority, as he did not want the advanced technology to fall into the wrong hands.
The two of them had regularly scheduled chess matches after that. Tchike had wanted revenge for his prior embarrassment, but believed like most that the Doctor was immortal. However, when he received the invitation for the auction of the Relic and an explanation of what it was, he thought it would be safe to finally kill the Doctor. The attempt failed, but Tchike expected him to return for their next chess match in 16 July 2070. (PROSE: Alien Bodies)