Suzuri no Tamashii (the soul of Chinese inkstone) (硯の魂)
Suzuri no tamashii' or 'suzuri no sei' is one of 'tsukumogami' (a type of Japanese spirits that originate in items or artifacts that have reached their 100th birthday and become alive) as described in "Konjaku Hyakki Shui" (literally, Supplement to The Hundred Demons from the Present and the Past), a yokai (Japanese ghosts, spirits, spooks and monsters) art collection book or supernatural bestiary by Sekien TORIYAMA.
It was originally an 'Akama suzuri,' a top-quality inkstone made specially in Shimonoseki City, but was possessed by a vengeful spirit of an Ise-Heishi warrior who had been defeated at the Battle of Dannoura.
It is said that when people use the 'akama suzuri,' they experience supernatural happenings such as hearing the waves, a fierce battle, someone's voice, and the "Heike monogatari" (The tale of the Heike) narrated, or seeing the water ripple like the sea in the inkstone.