Mount Tenpō: Former Lowest Artificial Mountain in Japan

Mount Tenpō

(Osaka City, Osaka)

【Yama (山)】means “mountain” in Japanese. About two-thirds of Japan’s land area is made up of mountainous regions, and there are over 18,000 mountains across the country. Among them, the most famous and most beautiful mountain (Yama) is Mount Fuji. On the complete opposite end of the spectrum is Mount Tenpō in Osaka, which was formerly the lowest mountain (Yama) in Japan.

If there weren’t a sign, you wouldn’t even know you were standing on Mount Tenpō, or even realize it’s a mountain at all. There’s a slightly taller mound right next to it, and people easily mistake that one for Mount Tenpō. It might make you wonder what a mountain really is.

Mount Tenpō was artificially created by piling up earth excavated from river construction work that began in 1831. At that time, it was about 18 meters high. It is said that more than 100,000 laborers were involved in the construction. Later, pine and cherry trees were planted, tea houses opened, and the area became a popular leisure spot for the townspeople. This lively scene was depicted in ukiyo-e prints by Utagawa Hiroshige, an artist who later influenced painters such as Van Gogh. His vivid prints show Mount Tenpō covered in lush greenery, with people enjoying boat rides and cherry blossom viewing under the blooming trees. The small rise of land was a scenic spot, offering views of the distant mountains surrounding Osaka and the islands floating in the sea.

In 1854, this scenic spot was destroyed. During Japan’s period of isolation, a Russian warship appeared off the coast of Osaka. In response to the incident, a battery of cannons was constructed on Mount Tenpō to defend the coastline. As a result, the mountain was shaved down, reducing its height to just 7.2 meters. In the end, the cannons were never actually used.

In modern times, by the 1970s, Mount Tenpō became even lower. Ground subsidence occurred due to groundwater pumping for industrial use, and as a result, the elevation dropped to 4.5 meters, making it the lowest artificial mountain in Japan.

Suddnly, Mount Tenpō eventually lost its title as the “lowest mountain” to Hiyoriyama in Miyagi Prefecture. After the Great East Japan Earthquake of 2011, Hiyoriyama was washed out by the tsunami and its elevation dropped to just 3 meters.

Even so, people in Osaka remain attached to the “number one” title, coming up with all kinds of reasons to justify it and quietly carrying on the battle of the low mountains. At the summit of Mount Tenpō, a sign proudly proclaiming it as “Japan’s Lowest Mountain” still stands.

Meanwhile, the Geospatial Information Authority of Japan, the official body responsible for surveying the country’s land, states that it does not officially recognize the lowest mountain in Japan. Incidentally, the mountain with the lowest elevation in Japan is Ogata Fuji in Akita Prefecture, whose summit is exactly at 0 meters above sea level.

If you’re worried about getting stranded on the world’s smallest mountain, don’t worry because local volunteers have formed a mountain rescue team, even though they’ve never once been called out for a rescue.

Please visit the official website Tempozan Park.