The island of Betio in the Tarawa Atoll was defended by the elite troops of the Special Naval Landing Force, whose commander, Admiral Shibasaki, boasted that "the Americans could not take Tarawa with a million men in a hundred years". In a pioneering amphibious invasion, the Marines of the 2nd Division set out to prove him wrong, overcoming serious planning errors to fight a 76-hour battle of unprecedented savagery. The cost would be more than 3000 Marine casualties at the hands of a garrison of some 3700. The lessons learned would dispel forever any illusions that Americans had about the fighting quality of the Japanese.