The Hokusai quadrangle (H-5) is one of fifteen quadrangles on the planet Mercury. It runs from 360 to 270° longitude and 20 to 70° latitude. Named after the Hokusai crater, it was mapped in detail for the first time after MESSENGER entered orbit around Mercury in 2011. It had not been mapped prior to that point because it was one of the six quadrangles that wasn't illuminated when Mariner 10 made its flybys in 1974 and 1975. These six quadrangles continued to be known by their albedo feature names, with this one known as the Apollonia quadrangle.