Seiko Sumo SPB101J1 Watch Review

If seizing opportunity were an Olympic sport, I’d be adorned in gold, standing triumphantly on the podium. Why, you might ask? Because in the grand arena of watch hunting, I caught sight of the Seiko SPB101J1, the “Sumo,” flexing its muscles on Amazon in a one-day sale. 

Watch collecting or whatever you want to call this sickness has us lusting for strange timepieces. For years I had seen the first and second-generation Sumo in Instagram pics, but it never really spoke to me. Then one day I saw some original artwork of the Sumo, and a spark ignited; I never really noticed how cool of a watch it was!

So, when I stumbled upon the Sumo on a daily deal, I snatched it up! Do you know how sometimes individual sellers will drop their prices? Well, I just happen to be searching “Seiko Prospex” on Amazon and was able to snag my Sumo for a lot cheaper than the normal $700 price it hovers around now.

Don’t be deceived by the nickname. While the “Sumo” may suggest a watch big enough to have its gravitational pull, Seiko has conjured up some horological wizardry to make this mammoth timepiece wear more like a featherweight champ. Not quite featherweight, but much smaller. It’s like fitting a sumo wrestler into a tailored suit — surprisingly sleek, yet unapologetically bold.

There are around thirty Sumo variations out there, starting with the first generation SBDC001 up till the newly released Seiko Sumo GMT. I picked the run-of-the-mill, plain ole black dial…and I couldn’t be happier. The Seiko Guy has a great article listing many of the models; see it here:

The Stock Sumo Bracelet…Which I Quickly Ditched!

Why Listen To Me?

I am a full Seiko fanboy, but I am not so blind that I can’t see the real fault with this watch or other Seikos. I own at least 25 Seiko watches, from Turtles, SKX’s, and even a beautiful SPB149. I know the brand and have real-world, actual experience.  I have owned my Seiko Sumo for over two years, so this can definitely be considered a longterm watch review.

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I can make it easy for you and save you some time; buy a Sumo! I love mine!

Before we dive deeper, let me bring up the big issue right now. My only complaint of the entire watch is the absolute garbage bracelet it comes with. It sucks so bad that it almost ruins the entire Sumo experience. Plus, the lug holes are so far outboard toward the edge of the case that a strap looks silly because it leaves such gaps.

Seiko SPB101J1 Sumo: A Quick Overview

Design and Build:

The Seiko SPB101J1, affectionately known as the “Sumo,” is a marvel in watchmaking that strikes a perfect balance between bold aesthetics and refined craftsmanship. Its substantial stainless steel case, measuring 45mm in diameter, is robust, yet the contours and the shaping make it wear much smaller on the wrist. The uni-directional rotating bezel adds functionality without sacrificing the watch’s sleek appearance.


At the heart of the Sumo beats the renowned Caliber 6R35. This automatic movement with manual winding capacity is a precise engine, providing an impressive 70-hour power reserve. It beats at a frequency of 21,600 vibrations per hour, ensuring that the hands move smoothly around the dial.

Dial and Hands

Protected by sapphire crystal, the Sumo’s dial is a thing of beauty. With Lumibrite hands and markers, it assures visibility in low-light conditions, adding a touch of luminous charm. The date function at the 3 o’clock position is a practical addition, making this watch as functional as it is stylish. I wish that Seiko used some AR coating here, but oh-well, they often disappoint us, even the fanboys. 

Water Resistance

Built for adventure, the Sumo boasts a water resistance of up to 200 meters. Whether you’re diving into the deep, going swimming or to the beach, or caught in a downpour, this watch is designed to withstand the elements.


The stainless steel bracelet sucks. Don’t even bother; just get a Strapecode after-market bracelet and save yourself the headache. 

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The stainless steel construction of the Sumo ensures robustness, making it suitable for daily wear and even more adventurous pursuits. The sapphire crystal protects the face, offering resistance to scratches and impacts.


The Lumibrite hands and markers provide excellent visibility in low-light conditions, ensuring that the time is always readable, whether you’re in a dimly lit room or exploring the depths of the ocean…or in a movie theater.

Value of the Seiko Sumo SPB101J1

In the bustling marketplace of wristwatches, where choices abound, and competition is fierce, the Seiko Sumo SPB101J1 makes a compelling case for itself. It isn’t just a watch; it’s an embodiment of Seiko’s commitment to offering high-quality timepieces at accessible price points. 

Let’s delve into what makes the Sumo a value champion:

Quality Construction

The Sumo’s robust stainless steel construction and sapphire crystal provide a level of quality typically found in more expensive watches. Its craftsmanship and finishing are reflective of Seiko’s attention to detail.

Reliable Movement

Powered by the Caliber 6R35, a movement known for its accuracy, reliability, and impressive 70-hour power reserve, the Sumo ensures that performance doesn’t have to come at a premium.

Diving Credentials

With a 200-meter water resistance rating and a uni-directional rotating bezel, the Sumo is equipped for serious diving adventures. Such functionality at this price range is a nod to Seiko’s dedication to providing real value.

Aesthetic Appeal

The Sumo’s design is unique and bold, offering an aesthetic that appeals to both enthusiasts and casual wearers alike. It’s a watch that doesn’t shy away from making a statement, yet it does so without being brash.


Equally at home in the office, on the trail, or under the sea, the Sumo’s versatility makes it a great all-rounder. Its design allows for both casual and formal wear, adding to its value proposition.

Resale Value

Seiko watches, including the Sumo, often retain a good portion of their value in the secondary market. For those considering resale, this is an additional aspect of the Sumo’s value equation.

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The Seiko Sumo SPB101J1 offers a delightful blend of style, functionality, and affordability. It presents a package that’s hard to match in its price category, making it an attractive option for those looking for a watch that delivers more than its price tag suggests.

Seiko 6R35 Movement: The Whole Reason I Bought The Sumo

The one thing that pushed me to pull the trigger on buying my Sumo was the price and the movement. A 70-hour power reserve is all I need to say!

Basic Specifications of the 6R36

  • Type: Automatic with manual winding capacity
  • Caliber: 6R35
  • Jewels: 24
  • Frequency: 21,600 vibrations per hour (6 beats per second)
  • Power Reserve: Approximately 70 hours

Features and Functionality

  • Date Display: Most watches using the 6R35 movement feature a date window, usually positioned at 3 o’clock.
  • Hacking Seconds: This movement supports the hacking seconds function, meaning that the second hand stops when the time is being set. This allows for precise time setting.
  • Hand-Winding Capability: In addition to its automatic winding, the 6R35 movement also supports manual winding, providing flexibility for the wearer.

Durability and Performance of the 6R36

The 6R35 movement is known for its reliability and robustness. Seiko has designed it with daily wear in mind, and it provides a stable and accurate timekeeping experience.

Comparisons with Other Movements

The 6R35 is an evolution of Seiko’s previous 6R15 movement. The main improvement in the 6R35 is the extended power reserve, which has been increased from around 50 hours in the 6R15 to 70 hours in the 6R35. This extended power reserve gives the wearer more flexibility, allowing the watch to be taken off for an extended period without needing a reset.

The Seiko 6R35 movement is a testament to Seiko’s commitment to providing high-quality, accessible automatic movements. With a balance of functionality and robust performance, it’s a movement that adds value to the watches it powers. 

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It’s particularly well-suited for those who appreciate the mechanical intricacies of watchmaking and seek a reliable movement without breaking the bank. Whether you’re a seasoned collector or a newcomer to the world of automatic watches, the 6R35 is a movement that delivers on its promise of quality and performance.

Pros and Cons of the Seiko Sumo


  • Build Quality: 
  • The Seiko Sumo is known for its excellent build quality, with a solid stainless steel case and bracelet.
  • Movement: 
  • The 6R35 movement is respected for its accuracy and reliability, with a substantial 70-hour power reserve.
  • Water Resistance: 
  • The 200-meter water resistance makes it suitable for serious diving activities.
  • Appearance: 
  • Its bold design and excellent finishing make it appealing to those who like a larger, more assertive watch.
  • Value: 
  • Offers a lot of features and quality for its price point, making it a popular choice among enthusiasts.


  • Size: 
  • The Sumo’s substantial size might not be suitable for those with smaller wrists or those looking for a more understated timepiece.
  • Weight: 
  • Due to its robust construction, it can be on the heavier side, which might be uncomfortable for extended wear for some users.
  • Bracelet: 
  • I mentioned it several times already; just get an aftermarket.

Should You Buy A Seiko Sumo?

Yes, yes, and thrice yes! If your heart beats in unison with Seiko, if your wrist aches for something that dances to a different beat, or if you have a penchant for the quirky, the Seiko Sumo is calling your name.

Embrace the Sumo’s individuality, and you’re not just buying a watch; you’re adopting a companion that reflects a love for the unconventional. Its unique design, reliable movement, and standout presence make it more than just a timepiece; it’s a statement, an expression of who you are.

So, if you find yourself drawn to Seiko, intrigued by the eclectic, or simply in love with wearing something a little different, then the Sumo isn’t just an option; it’s a must-have.

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Final Thoughts on the Seiko SpB101J1

The Seiko SPB101J1 Sumo is not just a watch; it’s a statement. It’s a testament to Seiko’s ability to create a timepiece that’s large but not overpowering, functional but not mundane. With a design that caters to both the aesthetically minded and the adventurous, the Sumo stands tall in the world of horology, delivering quality and style in a package that’s uniquely its own.

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