go-between vs tactician

go-between

noun
  • An intermediary or middleman. 

  • A shogi piece, used in chu shogi and larger shogi variants, that can move one step straight forward or straight backwards. 

tactician

noun
  • A person skilled in the planning and execution of tactics. 

How often have the words go-between and tactician occurred in a corpus of books? (source: Google Ngram Viewer )