Pentel Sign Pen S520 Review (Black, 1mm)

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Bottom line: The original fiber-tip pen, invented in 1963, used by a US President, taken aboard a NASA Gemini mission, and still being sold in essentially the same form today. It’s a broad-stroke writing instrument rather than a precision tool, and for the right use, it’s close to perfect.

Scribbright rating: 4.6 out of 5

Get the Pentel Sign Pen S520 on Amazon →

The pen that went to the White House

In 1963, Yukio Horie — who had founded Japan Stationery Company in postwar Tokyo in 1946, initially selling crayons and pastels to schools in a country rebuilding itself — launched the Sign Pen. The fibre tip pen was invented in Japan in 1962 by Masao Miura and Yukio Horie, who ran a business making art materials. The radically new writing device, equally suited to writing or drawing, was perhaps inspired by the writing brushes used in the East for centuries. The first tips were made of bamboo, but synthetic fibre soon replaced this.

The Sign Pen came to the attention of the world when it was spotted at a trade fair in the United States and subsequently fell into the hands of President Lyndon B. Johnson. Johnson used it to sign legislation. He used it publicly, repeatedly, and enthusiastically, and the American press covered it. A Japanese fiber-tip pen made headlines in Washington. Orders followed.

The Sign Pen was even taken aboard NASA’s Gemini mission. It was also taken aboard at my house, where Dad brought home boxfuls from his job as a graphic artist at the Ford Motor Company. So I’ve got plenty of childhood artistic scrawls and school papers, all done with a Pentel.

The S520 you’re buying today is the direct descendant of that pen. The acrylic fiber tip has replaced the original bamboo, and the barrel is now made from 83% recycled plastic, but the core design — fiber tip, water-based ink, color-coded cap and barrel — is fundamentally unchanged. Over 60 years of continuous production is an argument in itself.

What it actually is

The Pentel Sign Pen S520 is a capped fiber-tip pen with a 2mm acrylic nib that produces a 1mm line width. It’s not a fineliner. It’s not trying to be. The line it puts down is expressive and slightly variable, responsive to pressure and angle in a way that ballpoints and finer felt tips are not. It’s got a unique feel, I can honestly say; it’s a pen for writers who annotate with emphasis, for teachers who mark with intention, for anyone who wants their handwriting to look like it has weight.

The ink is water-based and non-permanent. It’s vivid; the black in this listing is a proper, saturated black, and the blue is outstanding, not the washed-out approximation you get from cheaper markers. And it flows freely without flooding. The ink dries quickly enough to avoid smearing in most normal use, though it’s not instant-dry and left-handed writers should exercise the usual caution.

The cap posts securely on the barrel and seals tightly enough to keep the tip from drying out between uses. Unlike the Staedtler Triplus Fineliner’s Dry Safe technology, the Sign Pen requires the cap to be on. Leave it uncapped for long and the tip will dry. This is not a desk abandonment pen. It’s a use-it-and-cap-it pen.

The 1mm question

The 1mm line width is the most important thing to know before you buy. If you’re looking for a fine annotation pen, a precise journaling tool, or something to use in a Hobonichi or a Moleskine where line width and bleed-through matter, this is not the pen. The Staedtler Triplus Fineliner at 0.3mm, or the Pilot Varsity if you want fountain pen feel, will serve you better for close work.

The Sign Pen is for different jobs. Whiteboard-adjacent work. Marking up printed manuscripts. Writing on index cards. Addressing envelopes. Signing things. Making notes in the margins of physical books where you want the annotation to be legible from across the desk. Writing that benefits from a little weight and character rather than precision. For those uses, the 1mm line is a real asset.

It also draws well. The line variation that comes from changing pressure and angle gives the S520 a quasi-calligraphic quality that finer pens can’t match. Writers who like to doodle in the margins, diagram ideas, or sketch rough maps between paragraphs will find the Sign Pen more natural than a precision fineliner.

The color question

The listing reviewed here is blue, which is the correct starting point after black. The Sign Pen range covers 12 colors including some less common options — ochre yellow, sky blue, grey, brown — that make the pen useful for color-coded annotation systems. The 12-color assorted set is the practical choice for writers who use color to organize thought rather than just to decorate. The pigment is consistent across the range, which matters when you’re reaching for a specific color mid-session and expecting it to behave predictably.

The color-coded barrel and cap make identification in a cup or a bag instant, which is a small thing that saves a disproportionate amount of time over a writing life.

The sustainability angle

The barrel is made from 83% recycled plastic. For a pen in this price range, that’s a true commitment rather than a marketing afterthought. The Sign Pen is not refillable, which remains the main sustainability objection; it’s disposable, and the environmental math on disposable pens is not great. But the recycled material content puts it considerably ahead of most competitors in the category. If the Pilot Varsity’s plastic footprint gave you pause, the Sign Pen is in better standing, though the truth stands that a refillable pen with bottled ink is the most sustainable writing instrument.

Pros

• Original fiber-tip pen; 60-plus years of continuous production and refinement
• 1mm line is expressive, pressure-responsive, and suited to annotation and marking
• Vivid, consistent water-based ink across 12 colors
• Color-coded barrel makes identification instant
• 83% recycled plastic barrel
• Excellent value per pen
• Cap seals reliably to prevent drying

Cons

• 1mm line width is too broad for fine journaling or detailed annotation
• Not refillable; disposable
• Water-based ink is not waterproof or permanent
• Requires cap to prevent drying; not suited to desk abandonment
• Cap-only design means no retractable convenience

The verdict

The Pentel Sign Pen S520 is one of the oldest and most historically significant writing instruments still in production, and it earns continued relevance not through nostalgia but through performance. For the jobs it was designed for — expressive writing, marking, annotation, signing, anything that benefits from a vivid 1mm line with character — it remains one of the best tools available at any price.

It went to the White House in 1963. It went to space. It’s now available in multipacks on Amazon for less than two dollars a pen. Progress, of a kind.

Get the Pentel Sign Pen S520 on Amazon →

Michael Semer is a writer and editor who considers a pen used by both Lyndon Johnson and NASA astronauts to be adequately field-tested.

Frequently asked questions

What is the Pentel Sign Pen S520? The Pentel Sign Pen S520 is a capped fiber-tip pen with a 2mm acrylic nib producing a 1mm line width, using water-based dye ink. It’s the direct descendant of the original Sign Pen launched by Pentel in 1963, which was the world’s first fiber-tip pen. The barrel is made from 83% recycled plastic and is color-coded to the ink.

Is the Pentel Sign Pen good for writing or just drawing? Both, though it excels at expressive writing, marking, and annotation rather than fine detail work. The 1mm line is too broad for close journaling or small handwriting, but it’s excellent for marking up manuscripts, writing on index cards, addressing envelopes, signing documents, and any writing where a bold, vivid line is an asset.

Why is the Pentel Sign Pen historically significant? It was the world’s first fiber-tip pen, invented in 1962-1963 by Masao Miura and Yukio Horie at what would become Pentel. It came to international prominence when US President Lyndon B. Johnson used it publicly to sign legislation, generating significant press coverage. The pen also accompanied NASA astronauts on a Gemini mission.

How does the Pentel Sign Pen compare to the Staedtler Triplus Fineliner? They’re different tools for different uses. The Triplus Fineliner has a 0.3mm metal-clad tip suited to fine writing, annotation, and journaling. The Sign Pen has a 1mm fiber tip suited to expressive writing, marking, and work where line character matters more than precision. The Triplus also has Dry Safe technology allowing days uncapped; the Sign Pen requires its cap to prevent drying.

Is the Pentel Sign Pen waterproof? No. The ink is water-based and non-permanent. It will run if wet and is not suitable for work requiring water resistance. The ink is also not fade-resistant for archival purposes; for permanent or archival documents, the Uni-ball Signo 207 is the better choice.

Is the Pentel Sign Pen refillable? No. It’s a disposable pen. The barrel is made from 83% recycled plastic, which partially offsets the environmental impact, but it cannot be refilled. For a more sustainable fiber-tip alternative, Pentel’s refillable markers are worth considering.

What colors does the Pentel Sign Pen come in? 12 colors: black, red, blue, green, brown, orange, yellow, grey, pink, sky blue, violet, and ochre yellow. Available in single pens, packs of 3, 6, or 12, and assorted sets.