Mt. Takamizu, is a mountain of 1977m in the Minakami/Gunma area. There are several routes, and for being Japan, it can partially be a reasonable challenging trek, where you may need to use both feet and hands. As the weather can be both wet and cold (even below 0), some of the rocks can become slippery. In fact, the mountain seem to have had quite a large number of accidents, so be prepared when going there.
During winter, there are a lot of snow, and the surrounding area have a couple of ski slopes.
How to get there
From Tokyo, take the JR Joetsu Shinkansen to Jomo-Kogen Station. From there, take a bus or Taxi to Tanigawadake Ropeway at Doaiguchi Station. The bus is very infrequent, so it is easiest to take a taxi.