From 29 February to 4 March the ROV "Kaiko" made three dives into the "central" basin, "Kaiko" #21 – "Kaiko" #23, . Depths ranged from at , to at ; dives #22 & #23 to the north, and dive #21 northeast of the deepest waters of the "central" basin. During the 1996 measurements the temperature (water temperature increases at great depth due to adiabatic compression), salinity and water pressure at the sampling station was , 34.7‰ and , respectively at depth. The Japanese robotic deep-sea probe "Kaikō" broke the depth record for unmanned probes when it reached close to the surveyed bottom of the Challenger Deep. Created by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), it was one of the few unmanned deep-sea probes in operation that could dive deeper than . The manometer measured depth of ± at for the Challenger Deep is believed to be the most accurate measurement taken up to then.