A Binary is a common formation of Clan military forces which consists of two Stars, making it equivalent to a light company in the Inner Sphere. Requiring only a modest increase in logistical support over a Star, Binaries are among the most common military deployments fielded by the Clans. A Binary can either be "pure," consisting of two Stars of the same unit type, or "mixed," consisting of two Stars of different unit types; both are used by all Clans, with the former having a slight edge in numbers. Binaries are commanded by a Star Captain.
Consisting of ten OmniMechs or, in second-line units, BattleMechs, 'Mech Binaries are sometimes organized by weight class, though they just as often will contain Stars of mixed weight. AeroSpace Binaries meanwhile consist of twenty OmniFighters or AeroSpace Fighters, commonly of mixed designs and weight classes, with naval Binaries consisting of ten to twelve vessels. An armor Binary will similarly consist of twenty Combat Vehicles, though given the Clans' disregard for conventional armor they are normally reserved for solahma or, more rarely, garrison units. An infantry Binary can consist of fifty Battle Armored Elementals or if conventional 250 infantry including a command squad. Few Clans bother to organize conventional infantry above the Binary level.
Mixed Binaries are only slightly less prevalent than pure formations among the Clans, the most common type of pairing being a Star of 'Mechs and a Star of Elementals. A Nova is similar to this type of mixed Binary, though it is technically still a Star formation, with two Novas organized into a binary referred to as a Supernova.
- MechWarrior's Guide to the Clans, p. 75
- Field Manual: Warden Clans, pg. 12
- Field Manual: Crusader Clans, pg. 10
- Field Manual: Warden Clans, pg. 10
- Field Manual: Crusader Clans, pg. 8
- Field Manual: Warden Clans, pg. 11
- Field Manual: Crusader Clans, pg. 9