Ton'a (頓阿?, 1289-1372), also spelled as Tonna; lay name – Nikaidō Sadamune 二階堂貞宗. A Japanese Buddhist poet, student of Nijō Tameyo 二条為世. Ton'a took a tonsure at Enryaku-ji Temple, but was later associated with the Ji sect 時宗 (founded by Ippen). He looked up to Saigyō's poetic genius. Here are two of his most well-known poems:

naku semi no
koe mo hitotsu ni
matsu kage suzushi
yama no takitsuse

Crying cicadas
are in one voice with the sound
that reverberates
– cool, in the shade of the pines –
from a mountain cascade.