Miyota 90S5 Review: A Reliable Open Heart Movement for Microbrands

Hello, fellow watch enthusiasts! Today, we're diving into the world of watch movements, specifically the Miyota 90S5. This Japanese gem has been making waves in the microbrand scene, and we're here to find out why.

Miyota 90S5 no date open heart automatic movement

The Miyota 90S5, produced by the Japanese company Citizen, is a marvel of precision and reliability. With a size of 11 1/2''', a height of 3.90mm, and a frequency of 28,800 vibrations per hour, this movement is compact yet powerful. It offers an impressive power reserve of over 42 hours and features 24 jewels, which reduce friction and increase the lifespan of the movement. The 90S5 also includes a stop second device, automatic and hand winding, and a 3 hands open-heart function.

Miyota 90S5 open heart automatic movement no date

But what sets it apart? Let's compare it with some of its peers.

ETA 2824-2: The Swiss Workhorse

The ETA 2824-2 is a Swiss movement known for its reliability and accuracy. With a diameter of 25.6mm and a thickness of 4.6mm, it's slightly larger than the Miyota 90S5. The ETA 2824-2 operates at the same frequency of 28,800 vibrations per hour and has a power reserve of approximately 38 hours. It also features 25 jewels, one more than the Miyota 90S5. While the ETA 2824-2 is a reliable workhorse, it often comes with a higher price tag, making the Miyota 90S5 a more affordable alternative without compromising on performance.

Seiko NH35A: The Durable Contender

The Seiko NH35A is another Japanese movement that is popular among microbrands. It has a larger diameter of 27.40mm and a total height of 5.32mm. The Seiko NH35A features automatic and manual winding mechanisms and includes 24 jewels. While the power reserve and frequency are not specified, it's known for its durability and reliability. The Seiko NH35A and the Miyota 90S5 are often compared due to their similar features and performance, with the Miyota 90S5 often being praised for its accuracy.

Sellita SW200-1: The Swiss Alternative

The Sellita SW200-1 is a Swiss movement that is often compared to the Miyota 90S5 due to its similar specifications. With a diameter of 26.00 mm, a height of 4.6 mm, and a frequency of 28,800 vibrations per hour, the Sellita SW200-1 closely matches the Miyota 90S5 in terms of size and performance. It also has a power reserve of 38 hours and features 26 jewels. However, the Sellita SW200-1 is typically more expensive, offering a higher level of finish and perceived quality.

Miyota 90S5 vs 9039: Sibling Rivalry

The Miyota 9039 is a sibling to the 90S5 and shares many of its features. Like the 90S5, the 9039 is an automatic movement with a size of 11 1/2''', a height of 3.90mm, and a frequency of 28,800 vibrations per hour. It also offers a power reserve of over 42 hours and features 24 jewels.

However, there are some key differences between the two. While the 90S5 includes a date display, the 9039 does not. This makes the 9039 a great choice for watch designs that don't require adate function, allowing for a cleaner dial design.

In terms of performance, both movements are known for their reliability and accuracy. They both fall within a daily accuracy of -10~+30 sec/day, ensuring that your watch will keep time accurately.

In conclusion, both the Miyota 90S5 and 9039 are excellent movements that offer high performance at an affordable price. The choice between the two will largely depend on the specific requirements of the watch design.

Whether you're a watchmaker looking for a reliable movement for your next timepiece, or a watch enthusiast curious about the mechanics of your watch, the Miyota 90S5 is a movement worth considering. Its balance of quality, performance, and affordability makes it a compelling choice in the world of watch movements.

So, next time you're admiring a microbrand timepiece, don't be surprised if you find the Miyota 90S5 or its sibling, the 9039, ticking away inside!

One of the microbrand watch companies using the Miyota 90S5 automatic movement is Borealis Watch Company namely in the Borealis Adraga series.

That's all for today, folks! Stay tuned for more watch movement deep dives. As always, keep ticking and keep smiling!


Remember, the world of watch movements is vast and varied, and while we've focused on the Miyota 90S5 today, there are many other movements out there worth exploring. Whether you're a fan of Japanese movements like the Miyota 90S5 and 9039, or you prefer Swiss movements like the ETA 2824-2 and Sellita SW200-1, there's a movement out there to suit every taste and budget. So, keep exploring, keep learning, and most importantly, keep enjoying your watches!