King Seiko Comparison: The Similarities And Differences Between The 37mm And 39mm Models

The king is back! But what if there are more kings to choose from? When Seiko reintroduced the King Seiko name early last year with a collection of 37mm watches, it was a stylish celebration of what makes King Seiko a beloved name among watch fans. A year on, we have seen only a select number of new King Seiko additions to the lineup, but Seiko announced new 39mm King Seiko models a little over a month ago. They were released alongside the spectacular 37mm King Seiko SPB365 limited edition. While that limited edition may have been a great eyecatcher, the new automatic 39mm models were exciting additions that will speak to many fans. We decided to go hands-on with both sizes and find out all there is to know.

If we go back to February, I vividly remember almost disregarding the new 39mm models at first. The King Seiko SPB365 limited edition with its spectacular brown turtle-shell dial was the main reason. We had that watch in the office, and I really enjoyed wearing it and eventually reviewing it. But Nacho and I found out that King Seiko also announced 39mm models in the official press info. They have the same attractive good looks but in a bigger size. We then quickly discovered there was much more to it than just a new size. They had a different automatic movement with a slightly longer power reserve and an added date window. On top of that, the 39mm watches also came with new dial executions. Could the 39mm size be the one for me? Or is last year’s 37mm the way to go?

Two different but beautiful King Seiko dials

Luckily, Seiko gave us the chance to follow up on that idea quickly. From the 37mm models, we had a chance to check out the SPB285 with its brown sunburst dial. While I saw it when it came out last year, it was a reintroduction to my favorite dial color of the 37mm lineup. Fratello’s own Thomas van Straaten owns the SPB281 with its vertically brushed silver dial, so that is the model I see frequently. As a result, I have come to greatly appreciate that watch. But from the get-go, that deep, dark brown dial seemed perfect for that retro King Seiko aesthetic, so I was happy to spend more time with the SPB285.

When it comes to the new 39mm versions, I had a chance to check out the brilliant-looking SPB369 with its spectacular linen dial. Pinpointing the color of this dial is not easy. While Seiko calls a white linen dial, it depends on the light. Sometimes it feels white, sometimes cream, and when you take a closer look, you see that there is an intricate pattern that looks spectacular with its different colors and shades. It does make you think of the great King Seiko pieces with linen dials from the 1960s. This ended up being a great duo of watches to compare, and they also happen to be my favorite versions in their respective sizes.

Introducing the new 39mm King Seiko range

As I only touched upon the 39mm King Seikos in my article, which was predominantly about the 37mm limited edition, let’s start with the specs of the bigger SPB369. It is part of a lineup of three models. The first is this SPB369 with its linen dial. The second is the SPB371 with a dark blue dial, and lastly, there is the SPB373 with a green dial. All three feature a case that is 39mm wide, just over 46mm long, and 12.1mm thick. The thickness is the same as that of the 37mm models, as is the water resistance rating of 100 meters.

The 39mm case is equally cool in its presence. The angular design with its long lugs looks even more impressive in this slightly beefed-up size with a box-shaped sapphire crystal. The finishing of the case is impressive and in line with what we have seen on the 37mm models. These new bigger versions have wider lugs that look even more impressive and give the case its character.

The finishing is an impressive mix of brushed surfaces and polished facets. The bezel features the same brushed or “hairline” finish on top and a mirror-polished, sloped side. Witnessing these pieces up close gives you an idea of how expertly finished they are. The quality and eye for detail are unmatched in the sub-€2K price bracket.

The spectacular linen dial of the SPB369

When you zoom in, you will find the beauty of the spectacular linen dial. This is also where you can start to spot the greater overall differences between the two different sizes, but let’s start with the dial itself. The linen texture is impressive. It looks stunning and would be my pick for the 39mm models. Additionally, it tells the story of the vintage King Seiko dials perfectly. The intricate pattern is executed nicely — although not as deep as some of the vintage Grand Seiko and King Seiko dials, as Thomas pointed out — and the impact is tremendous. I love a good linen texture as it adds so much depth to the dial.

If we then zoom in further on the different elements on the dial, it’s time to spot the differences with the 37mm model. First, the applied logo on the brown sunburst dial of the 37mm version features a brushed finish, whereas the logo on the 39mm model is polished. The larger version’s applied polished indices also differ from the smaller model’s hour markers, which have a fine pinstripe pattern on top. Another one of those intricate details can be spotted on the beautiful dauphine hands. The 37mm version has hands that are half polished and half satin-finished. The hands of the new 39mm model are fully polished. While these intricate details do not create a great difference in presence, it is very nice to see that Seiko has made an effort to make the 39mm look different.

The new in-house Seiko caliber 6R55

Inside the new 39mm version, you will find Seiko’s new in-house 6R55 movement. This updated version of the 6R35 operates at 21,600vph, has 24 jewels, and delivers a slightly increased power reserve of 72 hours. The three-day power reserve is also mentioned on the lower part of the dial. When it comes to accuracy, Seiko indicates that the new movement has an accuracy of +25/-15 seconds per day. While we know that Seiko likes to be conservative with those numbers, many manufacturers offer COSC-level accuracy at the same price point of just under €2K.

The movement will probably be a large part of the debate when it comes to the €1,950 price tag for the 39mm version, as it was with the versus the €1,800 37mm models. First of all, many purists would have liked to see a manually wound movement, but automatic movements are simply more popular these days. And as Thomas explained, the automatic 6R31 that powers his SPB281 is no horological marvel, but it has never let him down. From my experience owning multiple automatic Seiko models with 6R movements, I can only say that I have the same positive experiences. The 6R15 that powers my first-generation Sumo SBDC001 is one of the most reliable movements in my collection. While I am certainly no stickler for accuracy, I do care greatly about sturdiness and reliability, and I do not doubt that the new caliber 6R55 will offer just that.

Wearing the King Seiko watches

The additional 2mm might seem like a marginal increase in the diameter, but as it turns out, it makes a huge difference on the wrist. A fun detail is that Seiko chose to use the same bracelet for the 39mm versions as for the 37mm ones. This seven-row bracelet is a true joy to see and wear. The design is angular and almost technical but it perfectly suits the look of the case. The overall build quality of the bracelet is also very decent, and the finishing is on par with that of the case.

As Dave mentioned in his article about the 37mm models, you could opt for a 19mm leather strap as an alternative. But honestly, the bracelet adds so much more character to the watch that I wouldn’t wear it on anything else.

The butterfly clasp features a push-button release that is very easy to use. The clasp closes with a nice click and opens smoothly once you push the buttons on the side. It makes the watch very easy to put on and take off the wrist.

Wearing the King Seiko SPB365 and SPB385

Now, I understand that many watch fans will choose between these two based on how much of a connection they feel to vintage watches. The old-school charm is definitely in the 37mm version, despite both having an automatic movement. The date window (or lack thereof) could play a big part in your preference. The same goes for the size. I do not doubt that most of you will have your preference based on your wrist size. But what if you can pull off both sizes, as I can? Is there a logical choice? It’s obviously not that simple because watch preferences are not always based on logic.

But once on the wrist, you will find that there is a very distinct difference. The 2mm increase has a huge effect on overall wrist presence. It’s something you can probably spot in the pictures as well. I must confess that the wrist shots are of Thomas wearing both watches. Unfortunately, I was at home sick, floored by that ghost from the past we call COVID when the pics needed to be taken. Thomas has a slightly smaller wrist than I do and preferred the 37mm version. But a couple of days later, when Thomas saw me wearing both watches, he recognized that both sizes fit my wrist perfectly.

The details make the difference

But there is a big difference in presence that Thomas described perfectly. The 37mm SPB285 gives off that vintage King Seiko vibe we love so much. It’s like wearing a classic King Seiko. The 39mm SPB369 feels very much like a modern watch. Despite the same case and bracelet design, the watch also looks a lot more modern from a distance. It is a logical observation but not one that I necessarily felt while having them on the wrist. Both watches have the same design traits, after all.

Additionally, up close, you are looking for the right size for your wrist based on the visual presence and overall comfort. So it was good to hear Thomas’s observation because if you can pull off both sizes, that might be a deciding factor. I must say that the 39mm version wears incredibly well on my 18.5mm (7.3″) wrist. I love seeing the slightly bigger case because it accentuates the sharp lines and angles of that beautiful design even better. The date window is integrated perfectly and executed stylishly with its frame featuring a mix of brushed and polished finishes. And that linen dial is an absolute peach. The color and structure vary from different angles and in different lighting, and it is a joy to witness.

Final thoughts on the King Seiko SPB285 and SPB369

But don’t just forget about the beautiful 37mm SPB285. The charm of that watch is incredible. The sunburst brown dial might not be as instantly impactful as the linen dial of the bigger version, but it is a beautiful shade of brown, and experiencing it up close makes it so much more impactful than seeing the images online. On top of that, the 37mm version does have that vintage King Seiko charm that many of us love so much. It is a joy to wear and connects you perfectly to the King Seiko watches of the past. Within the Fratello team, most people prefer the smaller 37mm version because of its vintage character. With the 37mm case size and the dateless dial, it’s a watch that many of us love.

Having said that, everyone on the team also agrees that this new modern 39mm version is a great addition to the lineup and will earn plenty of fans. My preference? When Thomas asked me, I instinctively answered: “I’d probably go for the 39mm linen-dial version because it wears like a treat, and the dial is an absolute stunner. And I would focus on a vintage Hi-Beat King Seiko model from the 1960s if I wanted that true vintage charm.” And that is still my answer. I love this new addition to the collection a lot. But honestly, there is simply no going wrong with either of these two great King Seiko models. It does come down to personal preferences, and we have to compliment Seiko for giving us that difficult choice.

For more information, visit the official Seiko website.