Seiko Marinemaster 300 homages
The 1968 6159-7001 professional diver and the Marinemaster 300 references that follow its design.
44.3 mm across5 homages
See the 1
How to recognise one
Six marks make the look. The count says how many of the 5 homages keep each one.
Black dive bezel
A black bezel with bold white numerals every ten minutes and a lumed triangle at 12.
Large round plots
Big lumed circles mark most hours.
Double bar at 12
Two lumed bars stand side by side at 12.
Wide sword hands
Broad hour and minute hands filled with lume.
Date at 3
A flat date window sits at 3.
Crown at 4
The screw-down crown sits at 4, not at 3.
Each close-up covers about 12.5 mm of watch, using the listed case width and estimated photo edges.
The 1 that follow the SBDX001
Most marks kept first.
- Heimdallr Sharkmaster MM300
Price and size not listed yet
Drawn to scale by listed case width.
Original specifications
Sizes and specifications apply to the version named below. Other versions can differ.
SJE101
Assigned reference SJE101.
| Specification | Value | Sources and notes |
|---|---|---|
| Case width | 39.5 mm | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Lug to lug | 47.2 mm | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Thickness | 12.3 mm | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Lug width | 20 mm | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Movement type | automatic with manual winding | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Movement calibre | 6L37 | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Case material | stainless steel | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Crystal | box-shaped sapphire | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Water resistance | 200 m | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Power reserve | 45 hours | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
| Weight | 155 g | SJE101J1 | Seiko Watch Corporation One primary source. Value is stated for reference SJE101. |
Sources and unconfirmed details
- sje101-official.error.txt, read 2026-10-07
- sje101-seikoguy.error.txt, read 2026-10-07
- SJE101J1 | Seiko Watch Corporation, read 2026-10-07
6159-7001
Assigned catalogue reference 6159-7001. Vintage reference identity was matched by the explicit reference in the specialist listing/catalogue; dimensions describe reported examples and may vary with case condition.
| Specification | Value | Sources and notes |
|---|---|---|
| Case width | 44 mm | Seiko 6159-7001 listing | Fire KidsSeiko 6159-7001 listing | Sweetroad Sources agree. Fire Kids and Sweetroad give 44 mm, although Fratello reports 43.8 mm; the exact disagreement is retained. Sources differDirectly read sources report different values. The exact values remain separate and no averaging was applied. |
| Lug to lug | 50 mm | Reviewing an Icon: Seiko 6159-7000 Hi-Beat Dive Watch | Fratello One cited source. Fratello states that both 6159-7000 and 6159-7001 use 50 mm lug-to-lug. Sources differDirectly read sources report different values. The exact values remain separate and no averaging was applied. |
| Thickness | 14 mm | Reviewing an Icon: Seiko 6159-7000 Hi-Beat Dive Watch | Fratello One cited source. Fratello states both references use a 14 mm height. Sources differDirectly read sources report different values. The exact values remain separate and no averaging was applied. |
| Lug width | 19 mm | Seiko 6159-7001 listing | Fire Kids One cited source. Fire Kids lists 19 mm; no second exact lug-width observation was found. |
| Movement calibre | 6159A | Seiko 6159-7001 listing | Fire Kids One cited source. Fire Kids identifies calibre 6159A on its listed example. |
| Water resistance | 300 m | Vintage diver shootout | Fratello One cited source. Fratello reports 300 m for the 6159-7001. |
| Power reserve | 46 hours | Vintage diver shootout | Fratello One cited source. Fratello reports 46 hours for the 6159 movement. |
Sources and unconfirmed details
- Seiko 6159-7001 listing | Fire Kids, read 2026-10-07
- Vintage diver shootout | Fratello, read 2026-10-07
- Seiko 6159-7001 listing | Sweetroad, read 2026-10-07
- Reviewing an Icon: Seiko 6159-7000 Hi-Beat Dive Watch | Fratello, read 2026-10-07
SBDX001
Exact reference SBDX001 supplied by assignment.
| Specification | Value | Sources and notes |
|---|---|---|
| Case width | 44 mm | Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | FratelloSeiko Marinemaster: Is It The Quintessential Seiko Dive Watch? | Two Broke Watch Snobs Sources agree. The body-read sources Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | Fratello, Seiko Marinemaster: Is It The Quintessential Seiko Dive Watch? | Two Broke Watch Snobs identify reference SBDX001 and agree on case width mm at 44 mm. |
| Lug to lug | 50 mm | Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | Fratello One cited source. Fratello owner review reports 50mm. Two Broke Watch Snobs reports 50.5mm; conventions are unstated. Sources differDifferent dimensions; source gives no precision explanation. Exact-reference reviews differ by 0.5mm with no shared endpoint convention. |
| Thickness | 14 mm | Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | Fratello One cited source. Fratello reports 14mm on the exact reference. Other reviews report taller values without crystal/case basis. Sources differMaterial discrepancy between published measurements; no basis to pick one. Exact-reference reviews report different thicknesses; neither states the same crystal or measurement basis. |
| Lug width | 20 mm | Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | FratelloSeiko Marinemaster: Is It The Quintessential Seiko Dive Watch? | Two Broke Watch Snobs Sources agree. The body-read sources Fratello Editors Share Their Seiko Stories: RJ’s SBDX001 | Fratello, Seiko Marinemaster: Is It The Quintessential Seiko Dive Watch? | Two Broke Watch Snobs identify reference SBDX001 and agree on lug width mm at 20 mm. |
Sources and unconfirmed details
- Unresolved lug_to_lug_mm: available exact-reference body sources do not support a single value.
- Unresolved thickness_mm: available exact-reference body sources do not support a single value.
SBDX023Shown in the photograph
Measurements belong only to the photographed SBDX023 Marinemaster Professional 300m (direct successor to SBDX001). Other family references are not interchangeable.
| Specification | Value | Sources and notes |
|---|---|---|
| Case width | 44.3 mm | SBDX023 specifications One primary source. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
| Lug to lug | 50.5 mm | SBDX023 specifications One primary source. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
| Thickness | 15.4 mm | SBDX023 specificationsSBDX023 specifications Sources agree. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
| Lug width | 20 mm | SBDX023 specifications One cited source. CW Watch Shop body explicitly lists SBDX023 with 20 mm lug width. Its rounded 43 mm width is not selected against the exact maker 44.3 mm. |
| Movement calibre | 8L35 | SBDX023 specifications One primary source. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
| Water resistance | 300 m | SBDX023 specifications One primary source. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
| Power reserve | 50 hours | SBDX023 specifications One primary source. Japanese SBDX023 maker body gives width44.3, vertical50.5 and thickness15.4. Not SBDX001 or modern SJE101. |
Sources and unconfirmed details
- SBDX023 specifications, read 2026-10-07
- SBDX023 specifications, read 2026-10-07
More about the Marinemaster 300
Lay a homage over the SeikoAny of the 5, laid over the original at one scale
Lay a homage over the Seiko
Slide to fade from one watch to the other and compare the case shapes. The figures below describe the version shown in the photograph.
44.3Seiko Marinemaster 300
44Addiesdive MY-H7
40 mm placeholderHeimdallr Sharkmaster MM300
39Octopus Kraken OCT018
44San Martin SN0086 MM300 diver
44San Martin SN0087 1968 diverPhotos use listed case widths and automatic case-edge readings. The readings have not been manually audited. Photo proportions stay unchanged. Perspective and lug length can differ.Width unknown for one or both watches. The 40 mm placeholder does not show their true relative size. Photo proportions stay unchanged. Perspective and lug length can differ.Photos use listed case widths and automatic case-edge readings. The readings have not been manually audited. Photo proportions stay unchanged. Perspective and lug length can differ.Photos use listed case widths and automatic case-edge readings. The readings have not been manually audited. Photo proportions stay unchanged. Perspective and lug length can differ.Photos use listed case widths and automatic case-edge readings. The readings have not been manually audited. Photo proportions stay unchanged. Perspective and lug length can differ.
Seiko Marinemaster 300 photo: SBDX023. Addiesdive MY-H7 photo: MY-H7 green Marinemaster, steel bracelet.Case width unknown. Shown with a 40 mm placeholder.
Seiko Marinemaster 300 photo: SBDX023. Heimdallr Sharkmaster MM300 photo: MM300 Sharkey High Beat, blue-black dial, black bezel, steel bracelet.39 mm, 5.3 mm narrower than the Seiko
Seiko Marinemaster 300 photo: SBDX023. Octopus Kraken OCT018 photo: Black dial, gilt grooved dial, black bezel.44 mm, 0.3 mm narrower than the Seiko
Seiko Marinemaster 300 photo: SBDX023. San Martin SN0086 MM300 diver photo: SN0086-G blue dial, blue bezel.44 mm, 0.3 mm narrower than the Seiko
Seiko Marinemaster 300 photo: SBDX023. San Martin SN0087 1968 diver photo: SN0087-G black dial, gilt bezel.
SBDX023, specifications and sources
| Measure | Seiko | Addiesdive MY-H7 |
|---|---|---|
| Case width | 44.3 mm | 44 mm |
| Lug to lug | 50.5 mm | Not listed yet |
| Thickness | 15.4 mm | 17 mm |
| Lug width | 20 mm | 20 mm |
| Movement | 8L35 | NH35A |
| Power reserve | 50 hours | 41 hours |
| Water | 300 m | Not listed yet |
| Price | Not tracked here | about £104 $139, seen 2 Oct |
Side view
Copies
Not compared yet
Gives it away
No difference noted
The references, in order3 references, with the homages that follow each
Which Marinemaster 300?
3 of the 5 homages follow one named reference, and the rest copy the look in general. Select a reference to see its homages.