Natsume Yuujinchou is a manga by [url=https://myanimelist.net/people/3206/Yuki Midorikawa, which began its publication via LaLa DX in 2003 before the series moved to LaLa in 2008.
The titles are Suzu naru Kiri Kabu and Mugen no Kakera.
A special website for Natsume Yuujinchou Roku has announced that the series will get two new unaired episodes to bundle in 4th volume and 5th volume of the series’ Blu-Ray and DVD volumes to release on September 29 and October 25, 2017 respectively.