Growing market
Japan is one of the world's biggest robot markets.
According to some estimates, its overall robotics market was worth about 860bn ($8.4bn; £5bn) yen in 2012.
And with a rapidly ageing population, coupled with a falling birth rate, the demand for robots is expected to increase further.
The growth is expected to come not only from businesses looking to offset labour shortages and rising wage costs, but also from households seeking an alternative to paying for care workers for elderly relatives.
Japanese carmaker Honda has also been developing a household robot, Asimo. US President Barack Obama played football with it during his recent visit to Japan.