Koshiki-Yama is a twin-peaked mountain on the borders of Mamurogawa Town and Akita Prefecture. The mountain is entirely within the confines of the Kabu-yama Prefectural Natural Park. The mountain is a golden eagle and Hodgson's hawk eagle habitat with many parts untouched by humans. The steep cliffs and curious mountain shape means that much like the nearby Kabu-yama, there are many tales of Koshiki-yama as a famous ground for shugendo training. 

One of the peaks, Mekoshiki-yama, is home to a beech forest that is distinguished nationwide. The forest turns a refreshing green at the beginning of summer, and is also a popular spot for autumn leaves. There are a number of giant trees, including the Mekoshiki-yama Daikatsura chosen amongst the 100 giants of the forest by the Japanese Forestry Agency. 

Okoshiki-yama Loop (4.5 hours round trip)

The Okoshiki-yama loop takes in both summits by first going to the Okoshiki-yama summit. The return uses the Yashima Kaido Route previously used for Sankin-kotai during the Edo period. 

The trailhead lies at the end of the forest path of Maemori-yama. Pass through the beech forest path and the Danjo Col to the Okoshiki-yama summit. When returning, take the trail along the prefectural border to the mountain pass. Turn right, go via the Meisho-numa pond to the Yashima Kaido towards the east. Then simply head back to where you started. 

Along the way there is a beech forest. You will also see giant Katsura tree of Mekoshiki-yama, and the Karasu Boshi (crow’s hat) Rock. Bear in mind that there is a sheer cliff face in front of the Mekoshiki-yama. It is not standard to go to the summit. 

Okoshiki-yama Hiking Trail (2 hours one-way)

This is the shortest route to Okoshiki-yama. From the Kabu-yama forest road, take the Okoshiki-yama trail to the east. Head north-east at the Juji col. The trail from the Juji col has many steep parts and requires traversing the trail. Care must be taken here not to fall as the eastern side is very steep. From the summit there are views of Chokai-san, Gassan, Mamurogawa Town and Yuzawa City in Akita Prefecture. 

It’s possible to take the same path back. Alternatively, head north from the summit and make use of the Kenkyo Trail (prefectural border trail). Otherwise you can pass the Danjo Col to the Meisho-numa. Then go via the Kenkyo gorge to come out at the Otaki Trailhead.

Mekoshiki-yama Trail (30 minutes one-way)

This trail is for those who want to enjoy the stroll around Mekoshiki-yama. Take the trailhead at the end of the Maemori-yama forest road. Turn to the west at the beech forest heading towards the giant Katsura tree. This trail is quite basic so you don’t need much in way of special gear. However there have been Asian black bear sightings in recent years so be sure to take preventative measures. 

There is a famous water spring directly in front of the trailhead called Osuzu. This water spring is one of the top 100 springs in Yamagata.