As the last of the Vintage Grand Seiko series, the range of the 56GS series is second to none, even while utilizing only three different movements. No “special” or “VFA” examples in this series - but there are 35 different models! (1970 until 1974). Check the catalogues of 1971 V2, 1972, 1973 V1, 1973 V2, 1974 V1, 1974 V2, 1975 V1 and 1975 V2.
One can find the time only 5641A, the 5645A with date and the day-date 5646A, a nice range for sure, but more important is the fact that some automation was utilized and the beat rate adjusted to 28,800bph.
Some consider 28,800 bph to be the best, looking at maintenance, reliability and precision. Moreover, as a mass-produced watch, one can get maintenance parts easily even now, 40 years later. Of course, a slightly less finely tuned caliber 56 movement was also used in the King Seiko 56 series and the Lord-matics 5606.
The “Grammar of Design” rules... the -7010 and -7011 watches are almost certainly the most recognizeable vintage Grand Seikos that you see on the market today. There is almost no difference between the two apart from changing the indication waterproof to water resistance. It is not exactly clear when the change from -7010 to -7011 took place.
There were many -7000 cases produced for the 5645/6 movement and dials varied, For the -7010 the plentiful silver, uncommon white, the black and the navy. Gold cap models existed too.
At some time between 1972 and 1973, Grand Seiko swapped out the XQB011 bracelet for the XQB070. It is good to know that both will do, as it was probably just marketed as an after-purchase option.