Japanese name: Koyamaki, コウヤマキ, 高野槙.
Next to the main hall of Saimyo Temple 西明寺 at Mashiko 益子.

As I roughly understand from the sign below the tree, it is 30 mt. high, circumference: 4.5 mt, branches extension: 12 mt.
It is said that in the third year of the Jougen Era (1209), the Emperor Tsuchimikado planted this tree as a memorial in the occasion of the restoration of the main hall of the temple. The koyamaki takes its name from Mount Koya, in the Kii Peninsula, where this tree abounds. As in the Kanto region this kind of huge tree is rather rare, in the 29 year of the Showa Era (1954) this tree has been designated as a prefecture natural monument.