Moonman M600s

Overview

The Moonman M600s is a Chinese Duofold-style pen Garry has owned since early 2021, in a striking blue colourway he consistently describes as looking more like a dusty teal-grey-blue with real chatoyancy in the resin. He has compared it directly against two close rivals -- the visually similar Jinhao 100 and his own beloved Moonman M800 -- and has also experimented with swapping its stock fine nib for a HongDian/Kaigelu long-knife (architect-style) nib, turning it into one of his more unusual writers. Across multiple monthly rotations and three dedicated reviews, his feelings are consistently warm: he loves the colour and chatoyancy, finds it comfortable to write with, but has a long-running, repeated wish that it had a bit more heft to feel truly premium.

Design & Appearance

Shape: Classic Duofold-style silhouette, same width nearly the whole way down with gold-coloured banding -- visually very close to the Jinhao 100 and his Kaigelu 316/316a.
Colour: Marketed as blue, but Garry consistently describes it as more of a dusty teal or grey-green-blue, with genuine chatoyancy (a shifting, cat's-eye-like shimmer) in the resin that he repeatedly praises as gorgeous.
Cap: Flat black plastic top and a black plastic end finial bookending the coloured resin body -- a 'duotone' look he says he doesn't mind, distinguishing it from pens that try to look like a different, more expensive model. Two gold-coloured bands run around the cap (more than the single band on the Jinhao 100), which he finds more elegant. Clip is more of a Parker Arrow style -- springy but harder to get a finger under than the Jinhao 100's clip.
Section: Black, with a noticeably wide lip at the bottom that he specifically praised as being comfortable, in contrast to many narrower-lipped pens he finds digs into his finger.
Cap removal: A genuine criticism -- around three turns to remove the cap, which he repeatedly calls excessive (he prefers no more than 1.5 turns).
Posting: Does not post -- it perches very loosely and wobbles badly, confirmed across multiple reviews; he does not use it posted.
Pen Looks scores across reviews: 9/10 (vs Jinhao 100), 9/10 (vs Moonman M800 in blue), 8/10 (Majohn/Kaigelu nib Focus review) -- consistently one of the higher-scoring categories for this pen.

The Nib

Stock Moonman nib (most reviews)

Steel, gold-coloured, marked with the Moonman logo and crescent-shaped breather hole. Standard Moonman #6-size nib.
Only available in fine -- a recurring frustration Garry voices across multiple videos, as Moonman doesn't offer a medium option on this model.
Feels stiff, with minimal line variation under pressure; he describes it as smooth with a little feedback, generally pleasant but not exceptional.
In the direct M600s-vs-M800 showdown, he applied micro mesh to smooth the M600s nib before testing, which may have flattered its writing-experience score relative to the untouched M800 (Moonman nib) in that same video.

Swapped HongDian/Kaigelu long-knife nib (Majohn M600s -- Fountain Pen Focus)

Garry installed a long-knife (architect-style) nib from HongDian/Kaigelu in place of the stock Moonman nib -- a genuinely unusual configuration, made possible by the universal #6 nib housing.
Gives subtle, mild line variation (he describes it as 'slightly like an architect, only slightly') -- enough to add character without being dramatic.
Very wet and produces beautiful shading, though he specifically notes this combination needs careful handling for multi-page note-taking due to slow drying times (even after two minutes, some smudging remained in this review).
Audibly scratchy on the microphone but he clarifies it does not feel scratchy in hand -- a tactile, pleasant nib overall.
Reverse writing (upside-down/back of nib) is very scratchy with missing ink, as expected for a non-reversible nib of this style.
Writing Experience scores: 8/10 (M600s vs Jinhao 100), 8/10 (M600s vs M800), 8/10 (Majohn/Kaigelu nib Focus review).

Filling Mechanism

Cartridge/converter, with metal fittings that rule out eyedropper conversion. The included Moonman converter has internal agitator springs to help mix settled ink. Garry has directly compared the M600s converter against his M800 converter and confirmed they are identical/interchangeable despite initially looking smaller.

Measurements

Measurement	Value
Total length (capped)	14.0 cm
Length unposted	12.6 cm
Length posted	17.7 cm (very wobbly, not usable in practice)
Body width	1.27 cm
Cap width	1.49 cm
Section width	1.01-1.10 cm
Full pen weight	28 g
Body weight alone	18 g
Cap weight	10-11 g

Measurements are very close to the visually similar Jinhao 100 (within a millimetre or two on most dimensions) and slightly narrower than the M800.

Writing Experience (Ink Flow & Comfort)

Ink Flow scores: 8/10 (vs Jinhao 100), 8/10 (vs M800), 8/10 (Majohn/Kaigelu nib Focus review) -- a very consistent 8/10. No skipping or hard starts reported in any review with the stock Moonman nib.
Comfort: Praised repeatedly, particularly the wide section lip that's comfortable even for longer writing sessions. With the swapped long-knife nib, comfort was rated 8/10, with the one nitpick being the section feeling slightly thin -- a minor, deliberately picky note.

Inks Used (as referenced across reviews and monthly rotations)

Ink	Context / Notes
Robert Oster Great Southern Ocean	First Impressions video and February 2021 Pens In Use rotation; a grey-blue ink Garry felt matched the pen's colour beautifully
Robert Oster Tranquility	July 2021 'All Aussie Inks' rotation and the M600s-vs-M800 showdown -- a teal-leaning ink he says brings out the pen's true colour better than viewing it alone
Robert Oster Spearmint	Multiple photo-log entries (Pages 41, 46, 155)
Colorverse Albert	Majohn/Kaigelu long-knife nib Fountain Pen Focus review and a matching October 2023 photo-log entry -- a gorgeous green he specifically praised

Comparisons and Rankings

vs Jinhao 100 (dedicated showdown, Diamine Sapphire Blue vs Robert Oster Great Southern Ocean)

A close, visually similar pair Garry describes as both inspired by the same Parker Duofold lineage. He preferred the M600s's colour and chatoyancy over the Jinhao's more straightforward blue (9/10 vs 8/10 for looks), and preferred its dual cap bands aesthetically. Writing experience and ink flow were scored identically for both (8/10 each) -- he could not detect a meaningful line-width difference between the M600s's 'fine' and the Jinhao's 'medium' nib, despite the official size markings. The Jinhao 100 won clearly on value for money (10/10 vs 8/10) since it cost roughly ten dollars less.
Jinhao 100 = 8.5/10, Moonman M600s = 8.25/10

vs Moonman M800 (three-way showdown: M600s, M800 with Moonman nib, M800 with Bock nib)

The headline finding here was about nib quality rather than body design. Garry's blue M800 (with the stock Moonman nib, the same family as the M600s) wrote noticeably worse than the M600s in this video -- scratchy, dragging -- which he partly attributes to having worked on the M600s nib with micro mesh beforehand but not the M800's. The amber M800 with a swapped-in Bock nib was, by contrast, his clear favourite of the three, smooth and tactile ('like writing on Saturn,' as a viewer once described it to him). On pen looks, he rated the M600s highest of the three (9/10) for its more consistent chatoyancy, while penalising both M800s (8/10 each) for inconsistent patterning in the resin. Value for money favoured the M600s clearly given its lower price relative to both M800 variants.
Moonman M600s = 8.25/10, Moonman M800 (Moonman nib) = 7.5/10, Moonman M800 (Bock nib) = 8.25/10

Majohn M600s -- Fountain Pen Focus (with swapped HongDian/Kaigelu long-knife nib)

A dedicated solo review focused specifically on the nib-swap experiment. Garry directly compares the resulting line character favourably to his gold-nibbed Pilot Custom Heritage 92, noting the long-knife nib gives a different, more architect-like character even though it's a steel nib. He explicitly says he'd happily buy another M600s if the right colour came along, while noting he tends to reach for the cheaper, visually similar Jinhao 100 more often in practice (it's roughly ten dollars less and 'writes just as well').
Overall score: 8/10

Monthly 'Pens In Use' rotations and rankings

February 2021: Ranked position 6 of that month's lineup with Robert Oster Great Southern Ocean -- described as 'beautiful looking... absolutely gorgeous to look at,' with a nib that performs more like a medium despite being marked fine.
July 2021 ('All Aussie Inks'): Featured prominently with Robert Oster Tranquility, with Garry specifically noting the limitation of Moonman nibs only coming in fine as 'one of the things that really puts me off' the brand generally, even while liking this specific pen.
June 2022 ('Moon Landings' wrap-up): With the swapped Kaigelu long-knife nib installed, ranked position 2 for that month, just behind the Majohn A1, and ahead of the Majohn T5 and Moonman P135.

Overall Scores Summary

Review	Score
vs Jinhao 100	8.25/10
vs Moonman M800 (Moonman nib, three-way comparison)	8.25/10
Majohn/Kaigelu nib Fountain Pen Focus	8/10
Average	~8.2/10

By category (averaged across all three scored reviews)

Category	Average
Pen Looks	~8.7/10
Build Quality	8/10
Writing Experience	8/10
Ink Flow	8/10
Comfort	8/10
Value for Money	~8/10

Build Quality

Solid -- 8/10 in the one review where it was explicitly scored, with Garry noting nearly three years of ownership with no issues, easy cleaning, and an easy nib swap thanks to the universal #6 nib housing. The cap-removal turn count (around three turns) is his main mechanical complaint, alongside the pen's inability to post securely.

Value for Money

Generally solid but consistently edged out by the cheaper, visually near-identical Jinhao 100, which Garry says 'looks virtually identical and writes just as well' for roughly ten dollars less. He has explicitly said he tends to buy more Jinhao 100s as a result, despite continuing to like the M600s. He would still buy another M600s if a colourway specifically caught his eye.

Key Recurring Themes

Genuine chatoyancy and colour praised consistently -- repeatedly described as gorgeous, with the marketed 'blue' name not quite matching what Garry actually sees (more teal/grey).
A direct, repeated rival comparison to the Jinhao 100 -- visually almost identical, similarly priced, and a recurring 'which one would you buy' question Garry keeps returning to (with the Jinhao usually winning on value).
Limited to a fine nib from the factory -- a genuine, repeated frustration with the broader Moonman nib lineup, motivating his experiment swapping in a HongDian/Kaigelu long-knife nib.
Posts very poorly -- consistently wobbly when posted across every review; never used posted in practice.
Too many turns to uncap -- a specific, repeated mechanical criticism (around three turns).
A wish for more heft -- though not always stated outright, his comparisons with the heavier M800 and his repeated positive comments about weightier pens suggest the M600s's relative lightness is a mild, ongoing point of comparison.
The wide, comfortable section lip is a standout positive feature repeated across reviews.

Source Files

#summary