There is a width above broad. Fountain pen nibs differ at the edges, not the middle

Fountain pen nibs are built on four widths: extra fine, fine, medium and broad. Nearly every brand agrees that far.

The interesting part is outside that. Each maker bolts on widths of its own that the four do not cover.

Sailor's zoom and music

Sailor offers a zoom nib: hold it flat or upright and the line changes dramatically — closer to a brush than a pen.

And a music nib, originally for writing scores, laying down thick verticals and thin horizontals.

Neither is an exception at Sailor. Both have their own dedicated number inside the catalogue system, which means they are treated as part of the ordinary range.

TACCIA offers the same two, using the same names — its nibs are supplied by Sailor.

Pilot's medium-fine

Pilot offers FM, sitting between fine and medium.

That is a judgement that four steps are too coarse. Japanese has characters with many strokes: a fine can clog, a medium can bloat. There is a real gap to fill.

Kaweco's double broad

Kaweco offers BB — a step above broad.

European nibs already tend to write wider than Japanese ones, so a further step up puts it well beyond what someone used to a Japanese medium would picture.

Stubs at Montegrappa and Opus 88

A stub is ground flat at the tip, so verticals and horizontals differ in weight and the line gains rhythm.

Opus 88 goes further with flex nibs in extra fine and fine — nibs that spread under pressure, which few makers still produce.

The same "F" is not the same width

One more thing worth knowing: the same letter means different widths at different brands.

Japanese nibs are generally said to write finer and European ones broader — a Japanese medium is sometimes described as close to a European fine.

PencilDB records the designation, not the millimetre. So this data cannot settle whether a Japanese F is finer than a German F.

Notation varies too

How the width is written also varies: some brands pair the letter with a Japanese word, others use the word alone. Worth searching both ways.

(Compiled from the fountain pens recorded in PencilDB, August 2026.)