Seiko 5931-5300 from 1981

For sale is a Seiko 5931-5300.

From aluminum to white gold, Seiko experimented with different case material to manufacture their watch case throughout the years.

The Seiko 5931-5300 offered for sale here is made of hard alloy case (SHA) with a Vickers Pyramid Number (HV) around 700. Those who collect vintage watches might be aware of the hardened stainless steel (HSS) used in 6156-8010 and multiple quartz watches. Watches made of HSS are often found in incredible near mint condition attributed to the hardness of the HSS case.

To put things into perspective, HSS has a HV score of around 450 while the SHA has a HV score of around 700,making the SHA about 50% harder than HSS.

Needless to say, watch cases made of SHA withstand the test of wearing better than those made of HSS.

The multifacted watch case of the 5931-5300 coupled with the usage of SHA gives the wearer an immersive experience as the watch light bounce off the different facets of the case.

The watch is finished off with an understated rice paper textured dial to complement the eye catching case.

The watch is in immaculate condition other than some light signs of again on the dial.

The watch comes on a brand new leather strap.

Serial number has been covered for privacy.

Case Width: 30mm
Lug to Lug: 35.4mm
Thickness: 5.5mm
Lug Width: 18mm