The Merkava (Hebrew: About this sound מרכבה , "chariot") is a main battle tank used by the Israel Defense Forces. The tank began development in 1973 and entered official service in 1979. Four main versions of the tank have been deployed. It was first used extensively in the 1982 Lebanon War. The name "Merkava" was derived from the IDF's initial development program name.Design criteria include rapid repair of battle damage, survivability, cost-effectiveness and off-road performance.