The capital of Tochigi prefecture is Utsunomiya. It is also known as the Jazz town and houses many cocktail bars.
Major sightseeing spots in Utsunomiya are the following:
Futarasan Shrine is probably the most popular shrine in Utsunomiya. The front is lined by a massive stairway several stories in height before ending at a large temple.
Utsunomiya Castle, which once boasted of magnificence, is now a ruin castle park, an oasis in the city that is cherished by the local citizens.
"Ohya-ishi" is a stone that was created by volcanic activity more than 2,000 years ago. This green-colored tuff has warmth, is light and easy to process, and is quite durable. Because of its superior qualities, it is used in various structures.
There are some 200 gyoza specialty shops located throughout the city, all of them competing to make the tastiest dumplings. Gyoza dumplings are a mainstay of Chinese food, but have come to be ranked high among the foods enjoyed by the Japanese. 

Although Utsunomiya is a very important prefectural center and transportational hub, the most popular and attractive site to visit in Tochigi is Nikko wih its magnificent temples and the surrounding nature. 
Nikko is northeast of Tokyo and it takes 90 minutes to get to Nikko from Tokyo.
Nikko is regarded as one of the most popular tourist attractions due to the Toshu-gu, the Tokugawa shogun mausoleum, and is classified as “world Heritage”.(Tokugawa Ieyasu was the shogun, which gathered Japan and closed it for 250 years.)
The shrine took 15.000 of Japan`s best craftsmen two years to create, it was finished 1636. It distinguish itself significantly from other temple of this time. The temple in Nikko is richly ornamented and colored, and maybe it can best be described as the “Japanese rococo style”, with a lot of inspiration from China. Even tough the Tokugawa shoguns have been disappeared for many years, it still leaves traces that are deeply anchored in the Japanese. Nikko is also impressingly surrounded with beautiful nature. E.g. the lake Chuzenji and the cedar tree forest that surrounds the many temples that without problem mixes Buddhist and Shinto elements. In the autumn it is almost as the mountains explodes in fireworks when the leaves changes their color from green to yellow and red. 

Nasu is also a very popular tourist destination. It features hot springs, restaurants, shopping, themed attraction and at the very top Mt. Nasu offers great walking.