Mt. Tenno (天王山)
On the west side of the mountain, there is a border between Settsu Province (now Osaka Prefecture) and Yamashiro Province (now Kyoto Prefecture).
The name of the mountain comes from Yamazaki Tennosha Shrine (now Tamadeyori Matsurikitaru Sakatoke-jinja Shrine) enshrining Gozu Tenno (deity said to be the Indian god Gavagriva) on the mountainside.
Mt. Tenno is located at the south end of Nishi-yama mountain range on the west side of Kyoto Basin, and forms an isthmus with Mt. Otoko, east of Mt. Tenno. In this isthmus, along the course of the Yodo-gawa River into which the Katsura-gawa River (Yodo-gawa River system) and the Kizu-gawa River (Kyoto Prefecture) merge, JR Kyoto Line (Tokaido Main Line), Tokaido Shinkansen (bullet train), Hankyu Kyoto Main Line and National Route 171 (Old Saigoku Kaido Road) are on the right bank, and Keihan Main Line and Old National Route 1 (now Kyoto Moriguchi Line of Kyoto and Osaka Prefectural Road 13 and Old Kyokaido Road) are on the left. These are almost all routes between Kyoto and Osaka, which can be called the biggest major transport artery in the Kinki region including rivers which were once water routes. On the Kyoto Prefectural side, there is Oyamazaki Junction and Oyamazaki Interchange on Meishin Expressway where Keiji Bypass, which functions as a bypass of Meishin Expressway, diverges into Uji and Shiga (Meishin Seta Higashi Junction).
It is abundant in groundwater in this area and is famous for Suntory Yamazaki Distillery on the Osaka Prefectural side of the south foot. In the Kinki region, Tennozan Tunnel is famous for the traffic congestion on Meishin Expressway.
Because the area embraces the isthmus mentioned above, the scrambles occurred to get the strategically vital mountain in the period of the Northern and Southern Courts or in the Onin War, and yamajiro (a castle built on a mountain to take advantage of the mountain's topography) was built on it. Among them, in June, 1582, Mitsuhide AKECHI who killed Nobunaga ODA fought with Hideyoshi TOYOTOMI who was going to revenge for him at the Battle of Yamazaki. The battle has been expressed as the metaphor 'Tenka wakeme no Tennozan' (those who take hold of Mt. Tenno rule the world) which is still used especially in crucial matches or phases of sports or games.
Incidentally, Hideyoshi, the winner of the battle, built Yamazaki-jo Castle (also known as Hoshakuji-jo Castle or Hoji-jo Castle) there in the end of the same year, where he was based until his transfer to Osaka-jo Castle the next year.
Later, in Kinmon Incident at the end of the Edo period, Choshu clan captured the place to attack the Kyoto Imperial Palace, however, they were routed back eventually to have 17 Patriots including Izumi MAKI commit suicide there. Four years later, at the Battle of Toba and Fushimi, the army of former bakufu (Japanese feudal government headed by a shogun) set up camps separately in Hashimoto at the foot of Mt. Otoko and Oyamazaki on the other side of the Yodo-gawa River to counter the new government army. However, the Tsu clan in Oyamazaki switching to the new government army and shelling the former bakufu army in Hashimoto caused the former bakufu army completely collapsed and decided the outcome of the battle.
In Shogi (Japanese Chess), occupying the central square (in the fifth line of fifth row) means a lot where to be called Tennozan (Mt. Tenno).