To answer the demand for smaller mother ship and easy operation, light-weight type was designed and manufactured during 1987-1988.
　The light-weight type has unique points such as, 1 Articulations are smaller and lighter than prototype. 2 The number of water-tight space is reduced. 3 Every joints has the same structure.
　Because of new design mentioned above, even it has the same leg length as the prototype, the weight and hydraulic resistance can be reduced.
　As a result, the light-weight type weighs only 278kgf in the air and the maximum walking speed excessing 8m/min. has been achieved on the flat terrain in the test pool.