--- title: "Pilot Namiki Ink Cartridges: Fit, Capacity & Ink" canonical: "https://stationerytimes.com/guides/pilot-namiki-ink-cartridges/" description: "Pilot Namiki black ink cartridges explained: 12 per box, about 0.9 ml each, which Pilot fountain pens take them, the Japanese IRF-12S box, and water resistance." category: "Accessories" type: "Ink cartridges" published: 2026-10-22 updated: 2026-10-22 author: "Ellis Penhale" publisher: "Stationery Times" sources: 5 products: - name: "Pilot Namiki fountain pen ink cartridges, black, box of 12" brand: "Pilot" brand_origin: "Japan" made_in: "Not stated" material: "Water-based dye ink in plastic cartridges" price_band: "$ (under $5 per item, typical US retail, October 2026)" manufacturer: "Pilot Corporation (Japan); sold in the US by Pilot Corporation of America" model: "Namiki black cartridges, 12-pack (Goulet code PN69100); Japanese box IRF-12S-B" mpn: "IRF-12S-B" gtin: "4902505140617" url: "https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002578" --- # Pilot Namiki Ink Cartridges: Fit, Capacity & Ink > 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. - URL: https://stationerytimes.com/guides/pilot-namiki-ink-cartridges/ - Category: Accessories - Author: Ellis Penhale - Published: 2026-10-22 - Updated: 2026-10-22 ![A box of Pilot Namiki black ink cartridges with three black cartridges in front, and an inset of the sealed cartridge mouth](https://stationerytimes.com/images/raster/pilot-namiki-ink-cartridges-16x9.png) *The 12-cartridge box and three cartridges, drawn in proportion; box art is simplified.* Original drawing (SVG): . Drawings © 2026 Stationery Times, reusable with credit under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ## Product facts | Product | Brand | Brand origin | Made in | Material | Released | Price range (typical US retail, October 2026) | |---|---|---|---|---|---|---| | Pilot Namiki fountain pen ink cartridges, black, box of 12 | Pilot (by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America) | Japan | Not stated | Water-based dye ink in plastic cartridges | – | $: under $5 per item | - Made in (Pilot Namiki fountain pen ink cartridges, black, box of 12): 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: https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002578 ## 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. ![Ink per Pilot cartridge and per 12-box compared with a CON-40 fill and a LAMY T10 pack, drawn as bars to scale](https://stationerytimes.com/images/pilot-namiki-ink-cartridges-ink.svg) *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. That includes the [Pilot Metropolitan](https://stationerytimes.com/guides/pilot-metropolitan/), the [Pilot Kakuno](https://stationerytimes.com/guides/pilot-kakuno/), the [Pilot Vanishing Point](https://stationerytimes.com/guides/pilot-vanishing-point/) and the Custom 74. The pen usually comes with one cartridge, so this box is the refill. For how they compare with LAMY T10s and the two makers' converters, see our [best fountain pen ink cartridges](https://stationerytimes.com/guides/best-fountain-pen-ink-cartridges/). ## Are they the same as Pilot's Japanese cartridges? **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](https://stationerytimes.com/guides/pilot-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](https://stationerytimes.com/guides/platinum-carbon-black-ink/). ## 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](https://stationerytimes.com/guides/goulet-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. ## Sources - [Pilot (Japan): IRF-12S-B 万年筆用カートリッジインキ, web catalog (12 black cartridges, water-based dye, box 15 × 49 × 60 mm, 23 g, JAN 4902505140617, ¥550 incl. tax; not for Custom 823 or Custom Heritage 92; read October 22, 2026)](https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002578) - [Pilot (Japan): IRF-5S-B 万年筆用カートリッジインキ, web catalog (5 black cartridges, ¥330 incl. tax, JAN 4902505140655; ten colors)](https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002582) - [The Goulet Pen Company: Pilot Namiki Black ink cartridges (box of 12, 0.90 ml, proprietary, not water resistant, code PN69100; 113 reviews; read October 22, 2026)](https://www.gouletpens.com/products/pilot-namiki-black-ink-cartridges) - [The Goulet Pen Company: Best sellers (Namiki black cartridges at No. 63, October 22, 2026)](https://www.gouletpens.com/collections/best-sellers) - [JetPens: Pilot Black Ink, 5 cartridges (0.8 ml; identical to the Namiki 12-pack apart from packaging)](https://www.jetpens.com/Pilot-Black-Ink-5-Cartridges/pd/13574)