Reading the cleek marks of Tom Stewart, St Andrews

A small coiled serpent struck beneath the arc of lettering, on heads made before the pipe became the workshop's signature.

• — Sits high on the back, close under the arc rather than behind the hosel
• — Almost always paired with a smooth face and a long, thin blade
• — Lettering is finer and more crowded than on later heads

Caution: Genuinely scarce. A serpent on a heavy, short, dot-punched 1920s blade is the wrong mark on the wrong club.

A briar pipe in profile, bowl roughly the width of a match head, stem running to the right. The mark most collectors mean when they say 'pipe brand'.

• — Bowl small and shallow; the stem is the first part to wear away
• — Struck behind the hosel, usually with a hand-punched bench digit below
• — Commonly found with smooth or lightly dot-punched faces

Caution: Bowl size is the reading, not stem length. A worn stem tells you nothing; a small bowl on a low strike does.

The same pipe, noticeably bigger — bowl nearer the size of a pea — and set lower and further from the hosel.

• — Deeper, broader strike that survives polishing better than the small pipe
• — Frequently accompanied by 'Rustless' on stainless heads
• — The mark on the great majority of surviving Stewart irons

Caution: The changeover was gradual and the two overlap. Treat any single-year dating from the pipe alone as a guess. Received dating here is disputed.

The maker's arc, struck letter by letter above the pipe. On worn heads it survives as a faint curve of disturbed grain.

• — Individual letters sit at slightly different depths and angles — this is hand work
• — Reads cleanly under low raking light, badly under a bright lamp

Caution: Perfectly even lettering at a uniform depth is a machine, and a machine means somebody recent.

Stamped below the large pipe on the workshop's stainless heads.

• — Bright metal with little or no pitting after a century
• — Almost always paired with the large pipe and a plain line face

Caution: Condition here is alloy, not care. Do not pay a preservation premium for something the steel did by itself.

Auchterlonie, Anderson, Spalding, MacGregor, Wright & Ditson and dozens of professionals' shops, arced across the back of a Stewart head.

• — Retailer name and maker's pipe sit beside each other, both original depth
• — This is the normal case: Stewart sold heads to the trade by the crate

Caution: Be wary when a shop name is struck over the pipe, or struck shallow on an otherwise worn head.

One or two hand-punched digits below the pipe.

• — Consistent hand and angle across a genuine matched set
• — Wandering digits usually mean a set assembled from several sources

Caution: Widely read as bench, die or weight-run numbers rather than serial numbers. That reading is consensus, not documented fact. Received dating here is disputed.

Smooth into the 1900s, dot punching and deep corrugations through the late 1910s and early 1920s, plain lines after the governing bodies restricted deep grooves.

• — Original punching is worn hollow in the strike zone and sharp at the toe
• — Face pattern brackets a date more reliably than most people's pipe reading

Caution: A crisp, evenly cruel deep-groove face is usually a modern re-cut. Run a fingernail across it.