SEIKO PROSPEX SPB121J1 ALPINIST AUTOMATIC MEN WATCH

Why does the crown screw down, and what do I do about it?

It is what holds the 200-metre rating: a screwed crown compresses its seal against the case rather than relying on a push fit. The practical consequence is one extra step at either end of any adjustment. Seiko's instructions for this calibre put it plainly — unlock the crown before operating it, and be sure to lock it again afterwards. Get into the habit of checking the crown is screwed home whenever you have touched it, because an unlocked crown is the most common reason a water-resistant watch lets water in.

How do I set the time and the date?

Unscrew the crown first. At the first click, turning it moves the date. At the second click — which Seiko says to reach with the seconds hand at twelve — the seconds hand stops where it is, and turning the crown then advances the hands; wind them on until the date flips over, which tells you the watch is now reading the morning rather than the evening, then carry on to the correct time. Push the crown back in on a time signal and screw it down. One restriction matters: Seiko's instructions for the 6R35 say not to set the date between 9:00 pm and 1:00 am. Amending it then may cause problems such as the date failing to change the next day, and Seiko's end-of-month guidance adds that doing so may cause damage. Wind the hands clear of that window first.

What happens if I leave it unworn?

Nothing, for about three days. The 6R35 stores roughly 70 hours from a full wind, which is the reason this movement suits anyone who does not wear the same watch every day — a weekend in a drawer is comfortably inside it. Longer than that and the watch stops, which is normal rather than a fault: wind the crown by hand, reset the time and date, and it carries on. Bear in mind that a mechanical watch also needs enough winding to run properly, so a succession of quiet desk-bound days may leave it under-wound even while you are wearing it, and periodic maintenance is part of owning one.

How much water will the strap and the case take?

The case is rated to 200 metres, but the honest answer is governed by the strap rather than the case. Brown leather does not belong in a swimming pool or the sea — it stiffens, marks and eventually cracks once it has been soaked, so this is a watch to keep dry and to dry carefully if it is caught out. On diving: the specification lists a plain 200-metre rating with no diver's designation, so this is not a diver's watch and scuba diving calls for one that is marked as such. Treat 200 metres as a measure of how well the case is sealed, not as a depth you may descend to.

What is the inner ring for?

The specification confirms the watch has an inner ring that rotates independently of the dial, set from the case rather than by turning the outer bezel. What it does not tell us is what the ring is marked with, so we are not going to guess at it here — the product photography shows the scale itself. What is worth knowing is the general principle: a rotating inner ring is read against the hands, so whatever it carries, you align it with a hand and read the result from the ring.

What do the case dimensions mean in practice?

39.5mm is a moderate diameter by current standards, and 13.2mm of depth gives the watch real presence rather than letting it disappear under a cuff. The figure that would settle the question properly is the lug-to-lug span, since that is the dimension reaching across the wrist — and Seiko does not publish one for this reference, so we are not going to put a number to it. The leather strap takes care of the rest: it adjusts at the buckle, so there is nothing to size or remove.

What are the warranty terms?

Buying the SPB121J1 from City Chain Singapore, an authorised Seiko retailer, includes a 3-year warranty against manufacturing defects. It does not extend to accidental damage or to ordinary wear, and routine maintenance on a mechanical watch sits outside warranty work. Keep your warranty card and proof of purchase together, as the watch cannot be submitted for warranty service without them.