This 4840 is a very solidly made quartz - with backnumber 1977 it was made in the middle of the production run of the 48 base caliber, which spanned just four years.
In the first year of its production in 1975, only this Grand Quartz reigned supreme right next to the Quartz V.F.A with just three models, 8000/8010/8020, there were no other GQ calibers! The models 8030/8040 were introduced later in 1975 and made for just three years; they came with a thick steel band for the 4843 and with leather only for the 4840 & 4842. That setup never changed for this caliber. Even when the much daintier 48xx-8110 variation of this watch was introduced in 1977, ending the 8030/8040 production run in that year.
In 1978 Seiko introduced the twin quartz 9943, ending all of the 48xx caliber that year. The 48xx of the year before however remained a thicker and wider flaring watch (36x40x10mm!) and was more robust than its 9943 descendant - it is after all a Tanaka design. Therefore it already has a huge presence, apart from its very modern dimensions. This is also translated into the bracelet mentioned, which was uniquely designed for 1976/77 only. It is a quite heavy, very tight bracelet - almost like those of the King Seiko Vanac of the day.
This 48xx-8110 has a definite "butch" personality to it as evidenced by its measurements of course... It is a great early king of the 48s, with other variations like the 8040 just slightly larger with lugs of 19mm instead of 18mm and dimensions of 38x43x11mm. This watch is thoroughly understood and functioning perfectly - a true testament to the unparalleled quality of these early Seiko Quartzes.
Describing this watch reminds one of just that. For instance, the thermo-compensation, due to its relative thickness, is still excellent after all these years. The white sunburst dial work of course is impeccable, truly a high end watch. You noticed the black striped hands? It gives this watch something extra..... great legibility and some "punch". And that punch is also implemented in the mechanics of this watch, it has that special Seiko gimmick of the "jumping seconds hand". This means that it will jump ahead 10 seconds when you pull the crown to adjust the time. It makes time setting so much easier!
The Grand Quartz at hand is fully original with an original buckle, is not polished (retaining its sharp edges) and runs to specs.
In my experience these single quartzes are among the most accurate vintages; the twin quartzes like the 99 series mentioned have the specs for sure, but after 40 years or so… build quality and robustness gain the upper hand. The early Grand Quartzes truly shine!