square moated burial (ancient Japanese grave)

moated burial

a place of historical or archaeological importance; historic ruins; the remains of a previous civilization / land or position left by one who passes away; also, the person who inherits such

rectangle

important, significant

importance, consequence, significance

one thing

a grave, a tomb

a ditch / a groove / a gulf; a gap / disagreement between people / 10^38, hundred undecillion (American), hundred sextillion (British)

gutter / ditch / groove / furrow