"A tsunami wave that hit a coastal city in Iwate Prefecture after the March 11 massive earthquake is estimated to have reached 23.6 meters in height, a government-commissioned field survey by the Port and Airport Research Institute showed Wednesday," Kyodo News reports.
That's 77 feet, 5 inches. Or, about the height of a six- or seven-story building.
It wasn't a record, though. Kyodo says that:
"The tsunami wave measured in the city of Ofunato was lower than the domestic record of 38.2 meters [125 feet. 4 inches] marked in the 1896 Meiji Sanriku Earthquake Tsunami, and 34.9 meters [114 feet, 6 inches] logged in the wake of the 2004 earthquake off the Indonesian coast of Sumatra."