Calibre 591 — 20-jewel automatic

In brief

Between the 590 and the more refined 592 sits the 591, the 20-jewel variant of the compact 59x series.

Short history

Launched in 1960 alongside the 590 and the 592 in that same compact series, the 591 went into entry-level Seamaster models of the period, with centre seconds and Incabloc shock protection.

Watches that used it

• Seamaster (1960s)