ideal topography for the Four Symbols; geomantic configuration with four guardian gods
A traditional Chinese geomancy concept describing an ideal site layout: river to the east (Azure Dragon), broad avenue to the west (White Tiger), basin to the south (Vermilion Bird), and hill to the north (Black Tortoise). Used in historical city planning and feng shui contexts.
Heian-kyō is said to have been built on a site with ideal topography for the Four Symbols.
風水 is the broader practice of Chinese geomancy, while 四神相応 specifically refers to the ideal landform configuration with the four guardian gods.
四神 are the four mythological guardian gods themselves; 四神相応 is the topographical condition where the land matches their ideal arrangement.
From Chinese geomancy, combining 四神 (four guardian gods) and 相応 (correspondence, suitability). The exact historical derivation is uncertain, but the term is conventionally associated with ideal site selection in traditional East Asian city planning.