This is a bottle of liquid ink that can you can pour onto your ink pad to replenish the ink.
Shachihata is a Japanese ink brand from Nagoya established in 1925. They got their start with the groundbreaking self-inking stamp pad, the Mannen Stamp Pad. Now, they produce much more than stamp pads and are well known for manufacturing hanko, Japanese seal stamps. Hanko are widely used in Japan to stamp official documents, almost like a signature.