Udarnik (Russian: уда́рник; IPA: [ʊˈdarnʲɪk]) is an East Slavic and Yugoslavian term for a superproductive worker in the Soviet Union and the other ex-communist countries. The term is derived from the expression "udarny trud" for "superproductive, enthusiastic labour", which is often translated as strike labour (udar "shock, strike, blow"), and udarnik as strike worker, respectively.
Related terms are "Shock labour team" (udarnaya brigada, often translated as strike brigade) and "Udarnik of Communist Labour" (Ударник коммунистического труда), a Soviet honorary title. This is in contrast to the phrase shock troops, which is a translation from a German term.
This terminology is also seen in texts related to work in other Communist states, most notably in the People's Republic of China, North Korea, People's Republic of Bulgaria and Socialist Federal Republic of Yugoslavia.
In People's Republic of Poland a similar title was przodownik pracy (the leader of workship, also can be understood as the teacher (mentor) of [good] work). The term is a calque from another Soviet/Russian term peredovik proizvodstva, literally "leader in production", which was also a formal title of merit.
Most people familiar with this term understood it as the one who introduces superproduction, mainly based on the story of Wincenty Pstrowski, a miner who in 1947 achieved 270 percent of expected efficiency per month. Later Pstrowski died due to misconducted dental intervention, but in popular opinion it was due to deadly exhaustion.
Past 1956, the przodownik pracy title evolved into an equivalent of the employee of the month title given in the Western countries, but even then it was still disliked and eventually vanished.
In the socialist Czechoslovakia, an udarnik was called úderník (with slightly different pronunciation in the Czech and Slovak language). Úderníci were elite workers, who surpassed their work quotas and were used by the Party as propaganda. This norm-breaking, while usually real and often reaching astounding heights on the order of hundreds of percent of the original quota, was achieved at the cost of substandard quality, lack of work safety regulations and lack of concern for personal health. Most importantly, úderníci usually did not perform any minor tasks mandated by the norms they were supposed to follow. These tasks were performed by other workers, yet this work counted towards the úderník's quota. Notable udarniks from Czechoslovakia include Lumír Sakmar.