Compiled from 5 sources; we haven't tested this product ourselves yet. How we research
Quick answer
Pilot Namiki ink cartridges are Pilot's own proprietary fountain pen cartridges, sold in the US in boxes of 12. Goulet Pens lists about 0.9 ml of dye-based ink in each. They fit Pilot's cartridge pens, such as the Metropolitan, Kakuno and Vanishing Point, but not the Custom 823 or other brands. A box sits in our $ band.
On this page12 sections
The 12-cartridge box and three cartridges, drawn in proportion; box art is simplified.
Product facts
Product
Pilot Namiki fountain pen ink cartridges, black, box of 12
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Notes on these facts
Made by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America. Country of manufacture not stated: Pilot Japan's web catalog lists ink type, box size, JAN and price for the IRF-12S-B but no country of manufacture, and Goulet Pens' listing doesn't give one either. Pilot is a Japanese company; we didn't find a page naming where the US-packaged Namiki box is filled. Source. Price: example listing.
Price bands are typical US retail, checked October 2026. Conversions to US dollars are approximate, at October 2026 rates (US$1 = ¥158 = ₩1,330 = NT$32.5 = CN¥6.7 = SEK 9.9 = DKK 6.7 = ₺49.6 = C$1.41 = A$1.43 = CZK 21.7; €1 = US$1.12; £1 = US$1.32; CHF 1 = US$1.21).
Key takeaways
Each box holds 12 cartridges; Goulet Pens lists 0.90 ml per cartridge, about 10.8 ml a box.
Pilot Japan sells the same black cartridges as IRF-12S-B (12 per box, JAN 4902505140617) at ¥550 (about US$3.50).
Pilot says they fit all its cartridge fountain pens except the Custom 823 and Custom Heritage 92.
The black ink is water-based dye, so Goulet lists it as not water resistant.
Goulet ranked the box No. 63 on its best-seller list on October 22, 2026, with 113 reviews.
What are Pilot Namiki ink cartridges?
They are Pilot’s own pre-filled ink cartridges, sold in the US in an English-language “Namiki” box of 12. Namiki is the name Pilot used abroad for decades, and the cartridges inside are the same ones Pilot sells at home.
You push one onto the back of the pen’s grip, the feed pierces its seal, and the pen writes. On October 22, 2026, the black box was No. 63 on Goulet Pens’ best-seller list, with 113 reviews.
Pilot Namiki cartridge specs
Spec
Value
Maker
Pilot Corporation, Japan
US box
12 black cartridges (Goulet code PN69100)
Japanese equivalent
IRF-12S-B, JAN 4902505140617 (Pilot Japan)
Ink
Water-based dye (Pilot Japan)
Capacity
0.90 ml per cartridge (Goulet); 0.8 ml (JetPens)
Ink per box
About 10.8 ml (12 × 0.9 ml)
Japanese box size
15 × 49 × 60 mm (0.6 × 1.9 × 2.4 in), 23 g
Water resistant
No (Goulet)
Price band
$ (under $5 per box)
Pilot Japan lists the 12-cartridge box at ¥550 (about US$3.50) and the 5-cartridge IRF-5S box at ¥330 (about US$2.10), both including tax.
How much ink you get per cartridge and per box (Goulet, Pilot, LAMY figures).
Which pens do Pilot cartridges fit?
Every current Pilot and Namiki cartridge/converter fountain pen. Pilot’s Japanese catalog says they fit its cartridge fountain pens, except the Custom 823 and the Custom Heritage 92, which fill from a bottle.
Yes, apart from the box. JetPens says there is no difference between Pilot and Pilot Namiki cartridges besides the packaging and the number per package.
In Japan, the black 12-pack is IRF-12S-B and the 5-pack IRF-5S-B. Pilot Japan lists the 12-pack in black, red, blue and blue-black, and the 5-pack in ten colors, so some colors are easier to find in Japanese packaging.
How much ink is in a Pilot cartridge?
About 0.9 ml, per Goulet Pens. JetPens lists 0.8 ml for the same cartridge in Pilot’s 5-pack, so treat it as 0.8 to 0.9 ml.
That’s more than twice what Pilot’s CON-40 converter holds (0.4 ml), so cartridges are the bigger fill for these pens. A box of 12 gives about 10.8 ml in all.
How do you put a cartridge in a Pilot pen?
Unscrew the barrel, push the cartridge firmly onto the grip section, and screw the barrel back on. Goulet describes cartridges as sealed reservoirs you simply push into place; the pen’s nipple breaks the seal as it goes on.
Push straight and firmly until it stops, with the open end toward the nib. Then hold the pen nib down for a moment so ink can reach the feed before you write.
Goulet’s cartridge listing links a video tutorial that walks through the steps.
Is Namiki black ink water resistant?
No. Pilot calls it a water-based dye ink, and Goulet’s spec sheet lists it as not water resistant, not pigmented and not iron gall.
That makes it easy to flush out of a pen. For a waterproof black in the same pens, use a converter and a bottled pigment ink such as Platinum Carbon Black.
Can you refill Pilot cartridges?
Yes. Rinse an empty cartridge, fill it with bottled ink using a blunt syringe, and push it back on.
Goulet sells 5 ml ink syringes for this. It lets you keep using cartridges with any bottled ink, without buying a converter.
Where are Pilot cartridges made?
Pilot doesn’t say on the pages we read. Its Japanese catalog lists ink type, box size, JAN and price for the IRF-12S-B but no country of manufacture, and Goulet’s listing doesn’t state one.
Pilot Corporation is based in Tokyo; Pilot Corporation of America sells the Namiki-boxed version in the US.
Frequently asked questions
Do Pilot cartridges fit a Pilot Metropolitan?
Yes. The Metropolitan is a Pilot cartridge/converter pen, and Pilot says these cartridges fit all its cartridge fountain pens except the Custom 823 and Custom Heritage 92.
Are Pilot and Namiki cartridges the same?
Yes. JetPens says the only differences are the packaging and the count: Pilot's Japanese boxes hold 5 or 12, printed in Japanese, while the Namiki box sold in the US holds 12 and is printed in English.
Can I use Pilot cartridges in a LAMY or a TWSBI?
No. Pilot cartridges are proprietary and fit only Pilot and Namiki pens. LAMY pens take LAMY T10 cartridges, and many European pens take standard international cartridges.
How long does one Pilot cartridge last?
It depends on the nib and how much you write. Goulet lists 0.90 ml per cartridge, a little more than double the 0.4 ml Pilot gives for its CON-40 converter.
Can you refill a Pilot ink cartridge?
Yes, with a blunt syringe such as Goulet's 5 ml ink syringes: rinse the empty cartridge, fill it with bottled ink and push it back onto the pen.
Is Pilot Namiki black ink waterproof?
No. Pilot lists it as a water-based dye ink, and Goulet's spec sheet marks it not water resistant.
What colors do Pilot cartridges come in?
Pilot Japan lists the 12-cartridge box in black, red, blue and blue-black, and the 5-cartridge box in ten colors, including green, violet, pink, orange and brown.
