A design study on a storage ring light source is in progress at Tohoku University. The facility will be constructed at the site of Laboratory of Nuclear Science. There are a 300 MeV linac and a 1.2 GeV stretcher–booster ring operational, which will be used as injectors for the light source parasitically. The design of the storage ring has been modified to meet increasing demands for more insertion devices and more flux in X-rays. In the latest version, the beam energy is increased to 1.8 GeV and the emittance is reduced to 4.9 nm rad. Total number of the straight sections is increased to 16, two of which are 15 m long and reserved for long undulators or advanced devices in future. About 50 beam-lines can be constructed, while 15 of them will be constructed in the first stage.