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Sound comparison sample by tone color & shape (player: kotomen Yoshiaki Ookawa)

Sound comparison sample with new product and the one already in market (player: kotomen Yoshiaki Ookawa)

An innovative idea of “customizing sound with kotoji”.
※ Utility model registration obtained.

The first in the industry to use a cellulose nanofiber made from Japanese bamboos.
This new material,“Nanoforest”, is a registered trade mark of Chuetsu Pulp & Paper Co., Ltd.

3 types of forms to create different “brilliance” and “depth”
Type I, type II, small pillar (小柱)

Two types of “Tone colors”
―SORA― and ―MIKI―

Allows a very stable pitch ※ using non-slip tools.
Endures strong picks or frequently repeated picks which leads to a comfortable performance.

All items are sold “independently”. Purchase your combination of items.
Basic set: 12 Kotojis + 1 jinji(巾柱) + 1 shoji (小柱), non-slip sheet, tweezer for mounting
Customized selections: From one item to any combination of items.


Natural texture of the product due to plant origin materials.
Deep, full sound.
Easy to make large volume of sounds, the sounds linger.
Good for performance from classical music to modern koto music to POPS&JAZZ.


Has a natural texture of plant origin materials.
Brilliant sound unique to Koto.
Beautiful lingering fluctuating sound.
Good for performance from classical music to modern koto music to POPS&JAZZ.

New Kotoji – How are they different?

The new Kotoji is made of an organic material which adds “strength and gentleness” to the sound as well as the touch.
The material of the new Kotoji is a registered Biomass Mark product, easy to recycle, emitting less CO2 when burned.
In making of the new Kotoji, the “sound” was analyzed scientifically in collaboration with a university team.
Nature derived antibacterial substance is added to the material of the new Kotoji.

Additional information

Tone color



Type I, Type II, Half & Half, Small Pillar (小柱)

Set / Single

Set – 12 kotojis (箏柱) + 1 kinji (巾柱) + 1 shoji (小柱), non-slip tools, a tweezer for mounting, Single kotoji