Sakizō Yai was born on January 13, 1864, at the house of Yai, to a samurai family in the Nagaoka Domain (currently Nagaoka, Niigata Prefecture).[1] The Yai family was an upper class samurai family who held a property of more than 300 koku for generations, but at the age of six Sakizō's father died and the house went bankrupt. After this, his mother and his uncle took him over.[2]
In 1885, at the age of 21, Yai invented a continuous electric clock that ran on wet cell batteries. Electric clocks already existed, but they were to wind the power source spring with electricity, and that of Yai was a breakthrough in incorporating a self-made battery and running everything electrically.[2] This continuous electric clock was recognized as the first electric patent in Japan in 1891.[1]
In 1887, Yai was successful in inventing a dry cell electric battery.[1] However, he could not apply for a patent immediately because he could not pay the application fee for the patent,[3] and the patent for the first dry battery in Japan was obtained by the electrician Ichisaburo Takahashi. Carl Gassner patented the dry cell battery in Germany and Helensen patented the dry cell battery in Denmark in 1888.[1]
