Seiko's Cal. 03 was the world's first quartz movement small enough for ladies watches. It was produced by Suwa Seikosha starting in 1972 but was only produced in small numbers for high-end watches.

Seiko was raced to develop a quartz watch movement in the 1960s, and delivered their first Cal. 35 movement to the Neuchatel Observatory in late 1967, just a few months after the CEH delivered their "Beta" quartz movement prototypes. A product of Suwa Seikosha, Seiko offered Cal. 35 SQ for sale in the Seiko Astron watch on Christmas Day, 1969. Suwa rival Daini Seikosha developed Cal. 36 and launched it in 1970, but neither movement was truly produced in volume.

Suwa's second quartz movement was Cal. 03, which was a compact movement designed for high-end ladies and mens watches. Marketed as Cal. 03SQ, it was a simple time-only movement. No other version of this movement was produced, and it is said that as few as 90 examples were made before production stopped in 1973. The watches using this movement were cased in 18K gold and sold for over JPY800,000 in 1972, limited to just a few retail outlets.