ABISMO (Automatic Bottom Inspection and Sampling Mobile) is a remotely operated underwater vehicle (ROV) built by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) for exploration of the deep sea.

On 29 May 2003, Kaikō was lost at sea off the coast of Shikoku Island during Typhoon Chan-Hom, when a steel secondary cable connecting it to its launcher at the ocean surface broke.

RV Kairei (かいれい) is a deep sea research vessel that served as the support ship for Kaikō, and for its replacement ROV, Kaikō7000II.

Pressure hulls for electronic devices, a winch, a secondary cable drum and two electric transformers are located in the upper part of the launcher.

The craft successfully reached a planned depth of 9,760-meters, the deepest part of Izu–Ogasawara Trench, where it collected core samples of sediment from the seabed.

On 1–3 June 2008, during Leg 1, the Japanese robotic deep-sea probe ABISMO (Automatic Bottom Inspection and Sampling Mobile) on dives 11-13 almost reached the bottom about 150 km (93 mi) east of the Challenger Deep: "Unfortunately, we were unable to dive to the sea floor because the legacy primary cable of the Kaiko system was a little bit short.

[12][13] Leg 2, under chief scientist Takashi Murashima, operated at the Challenger Deep June 8–9, 2008, testing JAMSTEC's new full ocean depth “Free Fall Mooring System,” i.e. a lander.

The lander was successfully tested twice to 10,895 m (35,745 ft) depth, taking video images and sediment samplings at 11°22.14′N 142°25.76′E / 11.36900°N 142.42933°E / 11.36900; 142.42933, in the central basin of the Challenger Deep.