Baoshihua 宝石花 (gemstone flower) was the name Shanghai No. 2 Watch Factory chose for its line of watches containing the tongji movement. Beginning in 1972, it was the the first factory to sell them publicly, and this is an early model, possibly one of the earliest mass-produced tongji watches. Shanghai No. 2's early standard movements had a smaller balance wheel than later tongjis. The click on the earliest SZ1 movements was different from all later examples. Under this movement's balance is 2GG above SZ1.