The Scientific Deep-Sea Drilling Vessel "Chikyu", which is applying riser drilling technology proven in the offshore oil industry, can operate at deep sea and recover core samples by drilling the formations located under the seabed in the world. "Chikyu" will be an advanced drilling vessel having the capability to operate in the area with water depth up to 2,500 m at the initial stage. Furthermore, "Chikyu" will be upgraded to 4,000 m water depth capability. The target field of offshore oil exploration is moving into deepwater and ultra-deepwater areas, however, drilling in deepwater has faced challenges due to the characteristics of the deepwater environments. The challenges have forced the oil industry to develop innovative technologies and techniques. This paper describes the technical features of "Chikyu" applying and combining advanced drilling technologies, and introduce the innovative technologies which would allow us to solve the problematics encountered in the future deepwater drilling.