The International Ocean Discovery Program (IODP) is an international marine research collaboration that explores Earth's history and dynamics using ocean-going research platforms to recover data recorded in seafloor sediments and rocks and to monitor subseafloor environments. China is one of the members of IODP. Under the support of IODP-China, Dr. Fuqing Jiang was selected to staff the IODP Expedition 351 as a shipboard sedimentologist. This expedition was conducted in Armami Sankaku Basin (ASB) in the northern Philippine Sea with the research vessel R/V JOIDES Resolution from May 31 to July 30, 2014. The topic of this expedition is the Izu-Bonin-Mariana (IBM) Arc origins. The primary objectives include: (1) Determining the nature of the preexisting crust and mantle prior to subduction onset in the middle Eocene; (2) Identifying and modeling the subduction initiation process and initial arc crust formation; (3) Determining the Paleogene compositional evolution of the IBM arc; and (4) Establishing the geophysical properties of the ASB. Drilling at Site 351‐U1438 in the ASB recovered thick sedimentary and crustal records at 4711 m water depth. A 160-m thick section of Neogene sediment overlies 1300 m of Paleogene volcaniclastic rocks, and this volcaniclastic section was deposited on mafic volcanic basement rocks. The thin upper sediment layer is primarily terrigenous, biogenic and volcaniclastic mud and ooze with interspersed ash layers, which allow us to reconstruct the paleoclimate evolution of East Asia and the climate-modulated terrestrial inputs since Neogene. The recovered sedimentary and crustal records provide a unique opportunity to examine the inception and evolution of the IBM Arc.