Side by side

Seiko King Seiko KSKvsZelos Helica Moonphase

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

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What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Seiko King Seiko KSK

Owners and reviewers widely praise the King Seiko KSK's sharp, faceted case design and harmonious mid-century aesthetic. Its compact 38.1mm or 37mm size and slim 10.7mm thickness are noted as highly wearable. However, accuracy is a point of contention, with one reviewer reporting a wide range of +25 to -15 seconds per day for the 6R31 movement, while others criticize the standard 6R movement as too thick and a departure from the brand's history. Water resistance is consistently cited as limited to 50 meters, and one owner reported misaligned screws on the caseback and clasp. On balance, owners and reviewers find the King Seiko KSK appealing for its design and wearability, though the movement choice and accuracy are significant drawbacks for some.

From video reviewers

The Zaratsu polished facets and indexes are a strong point, replicating the original design. Reviewers questioned the high price point of the reissue.

Zelos Helica Moonphase

Owners widely praise the Zelos Helica Moonphase for its gorgeous aventurine dial, unique industrial-dress aesthetic, and comfortable wearability, with one owner calling it spectacular and another their favorite Zelos. The moonphase complication is frequently highlighted as beautiful, though some find the double moon distracting or the dial cluttered. A manual-wind movement combined with a screw-down crown is noted as a drawback by some, requiring adjustment and potentially feeling fragile when fully wound, while one owner reports a 43-hour power reserve. On balance, owners rate the Zelos Helica Moonphase highly for its stunning aventurine dial and unique design at its price point.

From video reviewers

The aventurine dial is a standout feature. The 39mm case size and short lug-to-lug are praised for comfortable wear. Reviewers did not agree on any specific weaknesses.

At a glance

14 of 29 specs differ
Diameter
King Seiko KSK38.3mm
Helica Moonphase39mm
Power Reserve
King Seiko KSK72h
Helica Moonphase
Water Resistance
King Seiko KSK100m
Helica Moonphase100m
MSRP
King Seiko KSK$2,000
Helica Moonphase$1,049

Full specifications

Case

6 specs
Category
Dress
Moonphase
Diameter
38.3mm
39mm
Thickness
11.7mm
10mm
Lug-to-Lug
46mm
39mm
Lug Width
19mm
20mm
Material
Stainless Steel
316L Stainless Steel

Crystal & Dial

4 specs
Crystal Shape
Box
AR Coating
Anti-reflective coating on inner surface
Dial Color
Meteorite
Lume
LumiBrite on Hands
None

Movement

3 specs
Caliber
Seiko 6R55
Sellita SW288-1
Power Reserve
72h
0h
Jewels
24
0

Pricing

1 specs
MSRP
$2,000
$1,049
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