The Seiko SPB417 Presage Sharp Edged Open Heart

Seiko’s Presage lineup falls into an interesting place within the wide world of Seiko. Between Seiko 5 Sports, Prospex, Astron, King Seiko, and the separate Grand Seiko, there’s a lot to take in. The Presage line is meant to highlight Seiko’s watchmaking chops by combining a traditional Japanese sense of aesthetics with traditional techniques. The result is a lineup of watches that are elevated over your standard Seiko offerings with more advanced finishing and dial work, most of which tend to lean a bit dressy. The SPB417 we’re taking a look at today is right at home in the Presage lineup, with some really intriguing dial work, crisp applied indices, and an angular case that shows off a variety of finishing techniques. Let’s take a closer look at this brand-new offering from Seiko and all it has to offer.


The Seiko SPB417 Presage Sharp Edged Open Heart

Stainless steel
Aitetsu blue with asanoha pattern
Stainless steel bracelet
Water Resistance
10 bar
40.2 x 47.4mm
Lug Width


Measuring 40.2mm wide by 47.4mm lug-to-lug, the SPB417 fits firmly in the mid-sized category. I would say that the measurements and case architecture line up, as the watch wears how the dimensions would imply. The watch is part of the “Sharp Edged” series, which debuted back in 2020 and has since grown to include several different models. One of the important features that’s new for the SPB417 is the addition of a mirror-polished faceted edge on the case of the watch that really helps cut down on its visual thickness. The case itself is made up of several angled surfaces that feature either brushed or polished surface treatments. By creating that visual contrast, it makes the case much more interesting than if they went all in on brushing or polishing. On the right side, you’ll find a signed push-down crown that’s adorned with the Seiko “S”. 

While the angular nature of the case makes it interesting to look at, the case remains traditional in design. A slim polished bezel surrounds the domed sapphire crystal. The lugs extend outwards and feature a straight angular stop at the ends. In profile, you’ll notice that the lugs curve downwards in a dramatic nature, and the transition is broken up by a mirror-polished facet. The resulting effect is a very slim mid-case that greatly diminishes the 13.5mm overall thickness of the watch. Around the back, the case back hangs well below the mid-case but nestles nicely into my wrist. Through the caseback, you can see Seiko’s new 6R5J movement inside which we’ll talk more about later. I do like the addition of the gold-toned rotor with striped finishing. 

Dial + Hands

One of the coolest parts of the SPB417 is the dial treatment. The Presage lineup is known for incorporating elevated dial finishing techniques into their designs, and this example is no exception. Featuring a pattern called “asanhoa,” the intricate geometric design is inspired by the hemp leaf. It’s been used for centuries, dating back to the Heian period over 1000 years ago where it was found on various Japanese textiles. The historic pattern is right at home on the dial of the watch. It’s rendered in a three-dimensional form, where Seiko has used stamping, color gradation, and an additional polished coating on top that makes it easy to get lost when looking at the dial. It has a genuine depth to it that really pops in the “aitetsu” or “indigo iron” colorway. The indices are intricate, with a very angular design that reflects light as you rotate your wrist. There’s a small portion of lume built into the outer side of each index, adding a level of functionality while still retaining a refined look. Pointing to the time is a set of sharp hands with a high polish and a healthy application of Lumibrite in the middle. The dial isn’t just about the underlying pattern though, there are two features that also set this watch apart from the rest, those being the open-heart aperture and the 24-hour display sub-dial.

At nine o’clock, you’ll notice the rather large aperture that shows off the escapement of the underlying 6R5J movement. It’s not just a hole in the dial though, there’s an interesting cutout made from a brushed metal that mirrors the asanoha pattern, but on a larger scale. As far as open-heart designs go, this is one of the few that I personally enjoy. It reads more as a skeletonized portion of the dial than just a fancy name for a hole that shows off the moving parts of the watch underneath. I also enjoy how it does bring a dynamic visual element to the dial, as you can see the balance wheel and pallet fork doing their thing.  

The second unique feature is the 24-hour display at 6 o’clock. It’s not without a quirk though — the hour hand on this sub-dial is tied to the main hour hand. So it’s not able to display a second time zone, and acts more as an AM/PM indicator that shows 24-hour time. It’s a bit of an odd complication since the watch leans dressy. When I think of 24-hour displays, my mind tends to gravitate towards military field watches or GMT watches where a second timezone comes into play. The sub-dial is finished beautifully though. It’s set into the dial with a slim mirror-polished ring around it. The face of the smaller dial has concentric circles and a sunburst effect, adding a completely different look to the accent. 

While the hands, dial, and complications are fun to look at, they do make the legibility suffer a bit. That’s not helped out at all by the double-domed sapphire crystal that lacks AR coating. Between the glossy dial, shiny hands, large open heart aperture, and wildly reflective crystal, the watch can be downright hard to read at times. It was one of the most difficult watches I’ve ever photographed because of the curve of the crystal. A little bit of AR coating could go a long way with the SPB417. It’s a shame because the dial has so much to offer, it’s just obscured a bit by the choice of crystal. 


Inside the SPB417, there’s a new movement from Seiko with a very solid feature set. The 6R5J is an automatic movement with 24 jewels that beats at 21,600 vibrations per hour. The movement can be manually wound and the seconds hand hacks for precision time setting. When fully wound, the impressive power reserve will last for 72 hours. Rated for an accuracy of +25/-15 seconds per day, the 6R5J won’t be rocking any master chronometer badges on the dial any time soon, but it’s still a solid and reliable everyday movement that makes sense in a watch of this price range. As a big Seiko fan, I would love to see their accuracy numbers tightened up a bit. The long power reserve and 24-hour display that the movement is capable of can open up some interesting options for other watches down the line as well. 

Straps + Wearability

The SPB417 ships on a stainless steel bracelet with a three-link design. The center links are flat with polished edges, while the outer links feature a more curved shape. A small clasp with a single micro adjustment hole keeps the bracelet closed. There’s a slight taper from 20mm at the lugs to around 18mm at the clasp. It’s not significant enough to really notice, making the bracelet feel pretty much the same width all the way around. The polished and brushed finishes on the bracelet pair nicely with the case. I’m not wild about the pin and collar adjustment system, but really you’re only going to have to deal with that once when receiving the watch and maybe another time in the Summer to throw in a half link. The watch would also look good on a two-piece leather or textile strap. 

On the wrist, the Presage Sharp Edged Open Heart is comfortable for all-day wear. The dimensions don’t really hide too much – it wears as expected. I will comment again on the slim mid-case and curved lugs. Seiko knows how to make a watch that hugs the wrist, and the SPB417 is no exception. 


Seiko’s new entry into the Presage lineup is a well-built and classy design. It would be right at home on your wrist in the office, as it leans a little bit dressy, but not overly so. I’m not so sure I’d find myself out on a fishing trip with this watch on my wrist, but the 10 bar of water resistance and sporty case could swing some light adventuring if you wanted to.

At right around $1200, the SPB417 backs up its price tag with a very solid dial treatment, premium case finishing, and a new 72-hour movement that’s genuinely handy for everyday use. If you’re looking for something a little bit different, like the idea of an open heart, but nothing really jumps out at you, there’s a pretty solid chance that this one might. Seiko

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Ed is a Long Island-based writer and photographer with an affinity for watches, fountain pens, EDC gear, and a great cup of coffee. He’s always looking for the best gear for the job—whether it be new watch, pen, flashlight, knife, or wallet. Ed enjoys writing because it’s an awesome (and fulfilling) way to interact with those who share the same interests.