Seimei 3.8m telescope (Okayama, Kyoto University) has the largest primary mirror for
optical-infrared observation in East Asia. One of its major characteristics is the quick
slewing capability. It can be pointed to a target in one minute as soon as a transient
event happens because of the ultra-light mounting. Another characteristic is the first
segmented primary mirror in East Asia. It consists of the world-first 18 petal-shaped
mirrors. 8 instruments are currently under development for observations of Superflares,
Black Hole Binaries, Gamma-Ray Bursts, Extra-solar planets and so on. In this talk, I
will report the development status of the telescope and some instruments.