As the reviews state, nantai is no joke. Unrelenting steepness from bottom to top. It took 6 of us 2 hours to summit and was definitely one of the harder climbs I've done. Views are all worth it when you finally finish.

Used the reliable bus service from Nikko to bus stop ‘Chuzenji Ibsen - stop 26’ from there it was a 10 minute walk with lake Chuzenji on your left where you will find the start of the walk inside of the shrine. It’s a 500 yen donation to start. From here you are confronted with a very steep incline from start to finish (about 2.5 - 4 hours) to the top, with challenging surfaces including rocks, mud and steps along the way. The path is clearly marked and well populated so it’s easily navigated. Once at the top though the views are outstanding on a clear day, and Mt Fuji can be seen in the distance towering above the clouds. Good walking boots, 3-5 litres of water and some food at the top definitely required. Some poles for the descent would have been handy too, as it is very steep. A hard walk but the end result is an excellent one, would recommend to anyone with a decent fitness level.