The hexagonal tortoise problem (Korean: 지수귀문도, Chinese: 地數龜文圖, a.k.a. jisuguimundo) was invented by Korean aristocrat and mathematician Seok-jeong Choi, who lived from 1646 to 1715. It is a mathematical problem that involves a hexagonal lattice, like the hexagonal pattern on some tortoises' shells, to the (N) vertices of which must be assigned integers (from 1 to N) in such a way that the sum of all integers at the vertices of each hexagon is the same.[1] The problem has apparent similarities to a magic square although it is a vertex-magic format rather than an edge-magic form or the more typical rows-of-cells form.[1]