Not exactly tokusatsu, but I think many will be interested. The fact is that the first film about giant (more precisely, just large) robots was shot in the Soviet Union in 1935. It's called "The Death of a Sensation" or "Jimm Ripple's Robot". Poster:
https://i.ytimg.com/vi/1PhhcdykZKw/hqdefault.jpg
But for a better understanding, it is better to look at the excerpt:
https://www.youtube.com/watch?v=-IdLBGM1pa0

The very origin of the word 'robot' has roots in the Slavic language.

Yes, from the word robota (work). So the first robots appeared in the play by the Czech Karel Capek. True, technically they are rather artificial people with a controlled brain, but still.

Sorry about the image quality.

https://i.imgur.com/toGQ0Xs.jpg