What are the most popular cycling routes in the Japanese Kita Kanto region?

The Kita Kanto region is renowned for the Iroha-zaka switchbacks in Nikko, the climbs around Mount Nasu, lakeside riding along Lake Chuzenji, and the historic Nikko Cedar Avenue. Cyclists also love the quiet forest roads through the Yamizo Mountains and rolling countryside between Nasu, Nikko and Ashino. These routes combine steady elevation gain with breathtaking mountain and cultural scenery.