JSK Laboratory, University of Tokyo · research humanoid
Kotaro
A child-sized musculoskeletal humanoid with 91 joints and 120 muscle actuators, soft tactile skin, two camera eyes and two microphone ears, powered by an external supply. It was built from June 2004 for the Prototype Robot Exhibition at EXPO 2005 in Aichi and sits between Kenta (2001) and Kojiro (2007) in the JSK line.
- Price
- —Not published
- Height
- 133 cmTaller than 25%
- Weight
- 20 kgHeavier than 9%
- Payload
- —Not published
- Speed
- —Not published
- Battery
- —Not published
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Why it matters
An early musculoskeletal humanoid with a flexible spine, shoulder blades and collarbones driven by 120 tendon actuators.
Real-world use
No customers or deployments reported yet.
How it stacks up
Against other humanoids that publish the figure. Pick a measure.
Kotaro is taller than 25% of the 305 other humanoids that publish a height. Bars show the 7 closest in date.
Kotaro is heavier than 9% of the 277 other humanoids that publish a weight. Bars show the 7 closest in date.
Kotaro has more joints than 99% of the 236 other humanoids that publish a joints. Bars show the 7 closest in date.
Not published by the maker: speed, payload, battery, price.
Public attention
A historic robot: no longer sold or in use, so it is not ranked against current humanoids.
- No Wikipedia article of its own yet
- No recent press stories listed yet
Measures how much people read and write about a robot, not how good it is. Measured 2026-10-14; same method for every robot. How it is measured
What’s inside
No component details published yet.
- Hands
- simple
- Movement
- Stationary · 91 joints
Lineage
Every University of Tokyo JSK Lab (Ikuo Mizuuchi, Masayuki Inaba) humanoid in order.
Made, sold and where
No production or sales figures published yet.
- Price
- Not published
- How to get one
- No official buying page found
Side by side with its peers
Picked by the same rules for every humanoid: another maker’s robot that moves the same way, is at the same stage and does at least one of the same main jobs, first shown within two years. Closer size and price rank higher. Few robots match closely, so these are the nearest matches. How we choose
| Measure | KotaroUniversity of Tokyo JSK Lab (Ikuo Mizuuchi, Masayuki Inaba) |  ECCE (ECCEROBOT)The Robot Studio and the EU ECCEROBOT projectSame job: research · Both fixed in place · Both past robots · Similar size |  HIROKawada IndustriesSame job: research · Both fixed in place · Both past robots |  DB (Dynamic Brain)ATR and JST ERATO Kawato Dynamic Brain Project, hardware by SARCOSSame job: research · Both fixed in place · Both past robots |
|---|---|---|---|---|
| First shown | 2005 | 2009-11 | 2009 | 2000 |
| Status | Retired | Retired | Discontinued | Retired |
| Height | 133 cm | 105 cm | — | 185 cm |
| Weight | 20 kg | 26 kg | — | 80 kg |
| Joints | 91 | 60 | — | 30 |
| Speed | — | — | — | — |
| Payload | — | — | — | — |
| Battery | — | — | — | — |
| Price | — | — | — | — |
Sources
Figures come from the maker. Every link below backs something on this page.
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