Opus 88 Demo Fountain Pen

Opus 88 Demo Fountain Pen

The Opus 88 Demo is the model that best explains why this Taipei brand has earned a devoted following among serious fountain pen users. Built from alternating clear and frosted resin in a flat-top cylindrical profile, it does something few pens manage: it makes the mechanics of writing visible. Every millilitre of ink in the barrel, every movement of the valve rod, every layer of sheen or shimmer in your chosen ink — all of it is on display, all the time. This is not decoration. It is a pen designed for people who want to understand what their writing instrument is doing.

Design & Construction

The Demo's form is deliberate and uncluttered. The straight-sided barrel and cap, flat finials, and alternating panels of polished clear and matte frosted resin give the pen a clean architectural quality that looks equally at home on a writing desk or in a shirt pocket. There are no tapers, no ornamental flourishes — just a well-proportioned cylinder that sits comfortably in the hand for extended writing sessions. Trim and hardware details vary by colour — see individual variants for specifications.

At 147.6 mm capped and 136.5 mm uncapped, the Demo is a large pen by any measure. The grip diameter of 11 mm and overall weight of approximately 27 g make it substantial without being fatiguing. Note that the Demo cannot be posted — the cap does not attach to the end of the barrel — so the length you write with is the uncapped length.

The pen is supplied in an Opus 88 gift box and includes a glass eyedropper pipette for filling.

Eyedropper Filling System & Shut-Off Valve

The Demo uses a full Japanese-style eyedropper filling system, with the entire barrel functioning as an ink reservoir. Ink capacity is approximately 3.56 ml — several times more than a standard converter and enough for days of continuous writing before a refill is needed.

What distinguishes the Opus 88 eyedropper from simpler implementations is the integrated shut-off valve, controlled by a twist knob at the base of the barrel. When closed, the valve seals ink above the feed, preventing the thermal expansion that can push ink through the nib when a warm pen is uncapped or carried. When open, it allows a steady, controlled flow from barrel to nib. The central valve rod can also be used to manually prime the feed — a detail that reflects the depth of engineering behind what appears, at first glance, to be a simple clear pen.

To fill: unscrew the grip section from the barrel, draw ink into the included glass pipette, deposit it into the barrel, and reassemble. Apply a thin layer of silicone grease to the barrel threads before closing to ensure a leak-free seal.

Nib Options

The Demo is fitted with a #6 JoWo stainless steel nib, manufactured in Germany. Available nib options include:

• Extra Fine (EF) — a controlled, precise line well-suited to small handwriting or detailed annotation
• Fine (F) — the most versatile everyday option for most writing styles
• Medium (M) — a broader, wetter line that brings out the shading and sheen in expressive inks
• Flex Fine — a responsive nib with line variation for writers who apply pressure variation
• 1.5 mm Stub — a broad italic-style nib that adds crisp line variation and distinctive character to every stroke

Opus 88 nibs write slightly broader than equivalent Japanese nib sizes. Writers accustomed to Pilot or Sailor fine nibs may wish to size down by one step.

Ink Display

The clear and frosted resin construction makes the Demo one of the most rewarding pens available for showcasing fountain pen inks. Shading inks reveal their full tonal range through the transparent panels; sheening inks catch the light from multiple angles; shimmering inks with fine metallic particles create a display that is genuinely difficult to replicate in any other pen. If you have an ink worth showing off, this is the pen to put it in.

Lifetime Replacement Guarantee

Every Opus 88 fountain pen sold at Shosai is backed by a lifetime replacement guarantee. If your pen is ever damaged beyond use, return it to our Gatineau boutique and we will coordinate a replacement directly with Opus 88 on your behalf. Full details, eligibility, and delivery options →

At Shosai

The Opus 88 Demo is available at Shosai's Gatineau boutique and through our online store, serving the Ottawa–Gatineau National Capital Region and fountain pen enthusiasts across Canada. Each pen is inspected before shipping. If you have questions about nib selection, ink pairing, or filling an eyedropper pen for the first time, we are here to help.