Note: This article is about polish custom of saluting with two-fingers. For information about offensive meaning of two-finger salute see article about it's close cousin: one-finger salute.
The salute is performed with extended middle and index finger touching each other, while ring and pinky fingers are bended and touched by the thumb. The tips of the middle and index fingers are touching the visor of the hat. The salute is performed only when covered.
Two-finger salute appeared in polish military forces propably before or during Napoleonic wars, or Kościuszko's uprising in 1794. Legends attributing creation of the salute to the Battle of Olszynka Grochowska during November's insurrection 1830-1831, are apparently wrong since Tsar's Viceroy in Poland, Grand-Duke Constantine was reported to say earlier that Poles salute him with two fingers because in the other three they are holding a stone ready to throw at him. All legends however attribute two-finger salute to the accident when some soldier saluted his superior (usually general) with wounded hand, from which ring and pinky fingers were detached as a result of a shrapnel explosion. As a remembrance all Poles are saluting using only two fingers.
The two-finger salute is said to cause problems for polish units serving with the Allies on the western front during World War II. Allied officers tought that polish soldiers saluting with two fingers are making fun of them or are deliberately trying to offend them. As a result many soldiers were arrested, and later explained by their polish superiors. This led to temporary using full hand salute when saluting foreign officers.