Fountain Pens

Ensso Piuma Minimalist Primary Manipulation 4 Review: A Limited Edition Fountain Pen with Real Character

A compact cigar-shaped fountain pen dressed in Jonathan Brooks' Primary Manipulation 4 resin, with a 14-karat gold fine nib and eyedropper capability. Here is what works and what to check before buying.

Published: 10/1/2026 Updated: 10/1/2026

Compact resin fountain pen with swirled blue and amber pearlescent finish on a concrete surface

Introduction

Ensso is a fountain pen brand based in Los Angeles, California, and its name blends the Italian name Enzo with the Japanese word Ensō, which refers to a hand-brushed circle drawn in a single stroke. The pen under review here is the limited edition Piuma Minimalist in Primary Manipulation 4, and it is one of the more interesting compact pens we have handled recently. Piuma is the Italian word for feather, a nod to the first pens, which were made from bird feathers.

This is a small run: only 90 pens exist, and at last check around 40 remained on the Ensso website. If the design appeals to you, it is worth acting sooner rather than later.

Design and Materials

The star of the show is the material. Primary Manipulation 4 is a Jonathan Brooks resin, and this PM4 iteration blends warm and cold tones with a fair amount of pearlescence throughout. Compared with the original Primary Manipulation, which shows starker contrast between colors, PM4 is more blended and wispy. In different light, it can look like a completely different pen, which is part of its charm.

Close-up of a swirled pearlescent resin fountain pen barrel showing blended warm and cool colors

Jonathan Brooks is widely regarded as a master resin maker, and it shows here. Lesser artisans can turn a palette like this into a muddled mess of colors, but this material retains depth and intentionality.

Size, Balance, and Comfort

The Piuma Minimalist has a cigar shape and is not a large pen. The top of the cap is rounded and angles up until about half an inch before the end of the cap, and there is no external branding or engraving anywhere on the pen. The cap-to-barrel transition is minimal and smooth, the barrel straightens for about an inch, then tapers to a rounded end.

In hand, it is well balanced and comfortable despite its modest size. The cap posts securely and, because it is very light, posting adds length without any meaningful back weighting. The cap edges are slightly rounded, so nothing digs into your palm during longer sessions. The section begins with a short steep flare, angles up to the threads, and has a medium-size step to the barrel.

Nib and Writing Performance

Under the twist-off cap, which comes off with a single rotation, sits a Bock number 6 14-karat gold nib engraved with the company name. The pen is only available in fine. Fine nibs are not for everyone, but this one performs well: it has a fair amount of feedback without being scratchy or sharp, offers some line variation, and the ink flow is decent for a fine point.

Fine gold fountain pen nib engraved on a fountain pen resting on paper

In practical use, the feed keeps up well during fast writing, and reverse writing works, though the line faded slightly at the end of testing. Paired with a lighter blue ink such as Seitz-Kreuznach Arctic Blue, it produces a clean, pleasant line that sits nicely between blues like Papier Plume Peacock Blue and Pilot Iroshizuku Ama-iro.

Hand-written fountain pen writing sample in light blue ink on white paper

Filling System

The pen is a cartridge-converter design that accepts standard international cartridges. One cartridge is included, and a converter is provided as well. The real bonus: it is also designed to be used as an eyedropper. An O-ring is installed at the end of the section, and the company states the barrel threads are carefully calibrated to stop ink flow, with silicone grease applied at assembly.

When examining our sample, the threads did not look obviously greased, so if you plan to eyedropper the pen, adding a touch more silicone grease is a sensible precaution.

Buying Advice

The Piuma Minimalist PM4 retails for $295 on the Ensso website and is sold only there. Given the 14-karat gold nib and the limited edition resin, the price feels reasonable. With only 90 pens made and stock visibly dwindling, hesitation is the biggest risk here; once this edition sells out, it will not return.

Small resin fountain pen posted and in use on a wooden desk with notebook

Conclusion

The Ensso Piuma Minimalist Primary Manipulation 4 is easy to recommend if you value standout resin work, a clean minimalist silhouette, and a fine gold nib that writes better than most. It is compact, comfortable, flexible in how you fill it, and genuinely limited. Just decide quickly: this one is not going to sit around.

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