The Sun Tzu-type was a Federation Starfleet starship of an unnamed class in service from the late-23rd century. The Sun Tzu-type was an Excelsior-class variant and appeared to be a predecessor of the 24th century Nebula-class. The type was equipped with a large dorsal, circular equipment module, and was armed with phaser banks and photon torpedo launchers. Two Sun Tzu-type starships, the USS Sun Tzu itself and an unnamed ship, participated in a battle alongside six other Starfleet vessels, including the USS Enterprise-A, near a ringed planet. (Ships of the Line 2011)