The 4843 is a very solidly made quartz - your watchmaker will love it! The production run of the 48 base caliber spanned just four years so they are becoming highly collectible! The 4843-5100 SGP (Solid Gold Plated) however, even more so as it was produced for two years only... read on.
In the first year of its production in 1975, only the 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 8030/8040/8041 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 was introduced in 1977, ending the 8030/8040/8041 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 (38x43x11mm!) and was more robust than its 9943 descendant - it is after all a Tanaka design.
The 4843-5100 launched in 1977 when the almost identical -5010 was no longer made, but remained available for just two years. Describing this watch reminds one of the thermo-compensation feature, due to its relative thickness it is still excellent after all these years. The dial work of course is impeccable, truly a high end watch. You noticed the black 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, is not polished 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!