Grand Seiko watch 5646-7010 Hi-Beat Vintage 1972 Blue Dial

As the last of the Vintage Grand Seiko series, the range of the 56GS series is second only to the 61GS concerning the diversity of watches produced. Whilst utilizing only three different movements and no “special” or “VFA” examples in this series, 35 different models were produced from 1970 until 1974. One can find them in the catalogues 1971-1975.

The 56GS used the no-date 5641A, the 5645A date and the day-date 5646A, making this the only series with all three complications. To make all the variations, for the first time automation was introduced into the production line, and the beat of the movement was set to 28,800bph which had great impact and reliability increased. Some people even consider 28,800 bph to be the best rate for a watch movement with its balance of maintenance, reliability and precision. As these movements were a work horse for Seiko at this time, it is easier to get parts for the 56GS even now, 40 years after its production, making it the most serviceable of all the Grand Seiko models produced in the past. Of course, a somewhat less finely tuned calibre 56 movement was also used in the King Seiko 56 series and the Lord-Matics 5606.

While there is a large variety of case designs, unlike the 61GS series, there is consistency in design and associated numbering of the cases used across the different movements.

Adhering strongly to the “Grammar of Design” rules, the -7010 and -7011 watches are almost certainly the most solid vintage Grand Seiko's that you see on the market today. It is believed that the difference between the two cases is simply a move from marking the cases as being “waterproof”, to “water resistant”, but this remains to be confirmed. It is not consistent however with the 5646 models seen, where both -7010 and -7011 references are marked as being “Water Resistant”.

The Grand Seiko 5646-7010 with the rare blue dial is a stunning blend of refined design and vintage rarity. The sharp case lines and polished surfaces showcase Grand Seiko’s “Grammar of Design,” but it’s that deep, elegant blue dial that truly sets this piece apart. Paired with the high-beat 5646 movement, it’s a rare gem that combines precision, beauty, and a touch of the unexpected—an understated icon for true collectors.