Decimation (Roman army)

Decimation (decimatio; decem = "ten") was a form of military discipline used by senior commanders in the Roman Army to punish units or large groups guilty of capital offences such as mutiny or desertion. The word decimation is derived from Latin meaning "removal of a tenth". The procedure was a pragmatic attempt to balance the need to punish serious offences with the practicalities of dealing with a large group of offenders.

Procedure
A cohort selected for punishment by decimation was divided into groups of ten; each group drew lots (Sortition), and the soldier on whom the lot fell was executed by his nine comrades, often by stoning or clubbing. The remaining soldiers were often given rations of barley instead of wheat for a few days, and required to camp outside the marching camp.

Because the punishment fell by lot, all soldiers in the group were eligible for execution, regardless of the individual degree of fault, or rank and distinction, unless rigged to eliminate the mutiny ringleaders. The leadership was usually executed independently of the one in ten deaths of the rank and file.

Modern instances of decimation
Italian General Luigi Cadorna allegedly applied decimation to under-performing units during the World War I. In his book Stalingrad, Antony Beevor recounts how, during World War II, a Soviet army division commander practiced decimation on deserters by walking down the line of soldiers at attention, and shooting every tenth soldier in the face until his pistol ran out of ammunition. This would be eight or nine men, depending on whether the commander carried his weapon with a loaded chamber or not.

Decimation can be also used to punish the enemy. In 1918, in the Finnish Civil War, the White troops, after conquering the Red city of Varkaus, summarily executed around 80 captured Reds in what became known as the Lottery of Huruslahti. According to some accounts, the Whites ordered all the captured Reds to assemble in a single row on the ice of Lake Huruslahti, selected every tenth prisoner, and executed him on the spot. The selection was not entirely random though, as some prisoners (primarily Red leaders) were specifically selected for execution and some good workers were intentionally spared.

Current usage of the word
The word decimation is often (counter to historical use) used to refer to an extreme reduction in the number of a population or force, much greater than the one tenth defined by the "deci" (as in "decimal") root. It is frequently used as a synonym for the word "annihilation" (the OED lists "annihilation" as meaning "to reduce to non-existence, blot out of existence", ) or for "devastation", (to lay waste) to which it bears a syllabic resemblance.