Hokusai is a rayed impact crater on Mercury, which was discovered in 1991 by ground-based radar observations conducted at Goldstone Observatory. The crater was initially known as feature B. Its appearance was so dissimilar to other impact craters that it was once thought to be a shield volcano. However improved radar images by the Arecibo Observatory obtained later in 2000–2005 clearly showed that feature B is an impact crater with an extensive ray system. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mercury they are named after deceased artists, musicians, painters, and authors who have made outstanding or fundamental contributions to their field and have been recognized as art historically significant figures for more than 50 years.
Image Source. Marker locations are approximate and may not always appear to align with image on map.