The round trip hike from the parking lot (or bus stop) is about 12 kilometers and takes about four hours depending on your own speed and the speed of the people in front of you. This is a popular hiking trail and gets quite busy on the weekends, especially during the autumn months when the foliage is changing to fall colors. The first half of the hike is mainly an upward climb, with a few flat areas, and takes you along a picturesque river and past several waterfalls. The hike to the top takes a bit over half the total time and you'll find yourself hiking along a dirt trail, rocks, manmade steps, and a couple of bridges across the river. Watch for signs along that way that point out some rocks that, when viewed from the right angle, suggest the shape of certain animals, such as "kaeru ishi" (frog rock). It's not a particularly arduous hike, but there are places where you'll be glad for the cables that are attached to the rocks as you use them to pull yourself up and over some of the rocks and steeper parts of the trail. If you take children along make sure they understand that the hike, like any hike, can be dangerous. You don't want them slipping on the rocks and sliding under the rope for what could be a long drop down to the cold river water. Also, it's a good idea to wear sturdy hiking shoes as some places along the trail are covered in loose gravel, or slippery from the water running off the valley's wooded walls. If you have hiking poles take them along; and a pair of those ever popular Japanese work gloves known as "gunte" (available in hardware stores or most any convenience mart) can save your hands from nicks or bruises as you clamber over rocks or use the cables and chains along the trail to keep you from falling.
Roughly 90 minutes from the trailhead (closer to two hours from the parking lot) you'll come to Nanatsugama-Godan-no-Taki, a beautiful five-tiered waterfall. It's possible to climb down and over the rocks to get closer to the waterfall for a picnic stop. There are other spots along the trail where it's possible to stop and have lunch or a snack break as you admire the scenery. However, most people continue to the top of the trail where there are a few rough hewn benches and a wooden platform where you can sit and have the picnic lunch you've brought along. There is also a toilet here and it's the only one since just before the trailhead. Be sure to bring along bottles of water, too, as there is no place to get water along the hike.
Keep going after the top of the trail and one you cross the river the road down is not much more than a walk through the forest along a well packed smooth path that is more of a road than it is a trail. Note the steel rails that are along parts of the path and in some places jutting out into space over steep drop offs. In days past these rails were used for flatcars to haul the cut timber down from the mountain. The flatcars were pulled up the mountain by horses and the loggers would load the trimmed logs on the cars for the ride down the mountain where the logs could be dumped into the river to be floated on down to the mills. As you walk down you'll see one of the flatcars with logs stacked on it depicting what they looked like long ago. Getting there: by car take the Chuo Expressway from Tokyo to the Katsunuma exit. Follow route 20 west to highway route 140. Go north to Nishizawa Keikoku (roughly 2.5 hours from Tokyo). By train take the JR Chuo Line to Yamanashi-shi Station (95 minutes by direct limited express train- about 4000 yen one way - from Shinjuku Station. From Yamanashi-shi Station, there are 3-5 bus round trips per day to the trailhead of the Nishizawa Gorge. The bus ride takes about one hour and costs 900 yen one way. If you decide to make it an overnight trip there are numerous Japanese inns along route 140 or within a hour's drive from Nishizawa Gorge. For an English language website of some hotels in the area see: http://www.japanican.com/ A map is available at: https://maps.google.com/maps?hl=en&ie=UTF-8&q=%E8%A5%BF%E6%B2%A2%E6%B8%93%E8%B0%B7%E9%9B%BB%E8%A9%B1%E7%95%AA%E5%8F%B7&fb=1&gl=us&hq=%E8%A5%BF%E6%B2%A2%E6%B8%93%E8%B0%B7%E9%9B%BB%E8%A9%B1%E7%95%AA%E5%8F%B7&hnear=%E8%A5%BF%E6%B2%A2%E6%B8%93%E8%B0%B7%E9%9B%BB%E8%A9%B1%E7%95%AA%E5%8F%B7&cid=0,0,10334973919460279936&ei=jepXUav-Os6fiQfJu4H4Ag&sqi=2&ved=0CK0BEPwSMAA