This is a mid-grade naphtha soot ink stick made from mineral oil soot.
When used as thick ink, it produces a deep, solid black tone, and when used as light ink, it reveals a purplish-brown shade.
Ideal for practicing Kanji and for large-character calligraphy works.
The largest size available from Nanshōen, the 20.0 model, has an impressive appearance and is also recommended as a gift.