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Mass-produced#5 in family

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Movement tier: unclassified · caliber IWC Cal. 52610: in-house automatic with perpetual calendar, 21,600bph, 60h PR, 37j; perpetual calendar with four-digit year display; jumping date; used in Portugieser IW5033 · 60h power reserve (2.5 days)
Large case: suits wrists 7 in+ (18 cm+)
44.2 mm case. A bold, statement-size wear. Best suited to larger wrists where the case sits flush.

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Authentication

Both the 7-day power reserve display and all perpetual calendar functions must advance correctly; any mismatch indicates service need.

Known issues in the market
  • The 7-day power reserve means the watch is wound infrequently; verify the rotor turns freely through the caseback.
  • Pellaton winding with ceramic bearings is the Cal. 52610 architecture; confirm through caseback.
AreaWhat to checkWhat is correctRed flag
dial7-day power reserve and perpetual calendar indicationsPower reserve indicator and all perpetual calendar functions (day, date, month, year) reading correctly and advancing in synchronizationAny perpetual calendar indication lagging; power reserve indicator not moving after winding
casebackCal. 52610 with Pellaton windingCal. 52610 confirmed through caseback; Pellaton ceramic bearing pawl architecture visible; rotor turning freelyAny caliber other than 52610; rotor not turning freely; standard ratchet without Pellaton architecture
casePortugieser case with no external pushersPortugieser round case with crown-only correction mechanism; no external pushers for calendar correctionAny external pusher holes on the case band; Portugieser perpetual calendar uses crown and caseback correction only
Common legitimate replacements
  • Original IWC Portugieser strap or bracelet; factory replacements are standard.
Expert resources: IWC Portugieser Perpetual Calendar IW503302 product documentation. IWC Cal. 52610 technical sheet.

Authentication guide

Last reviewed June 2026

The IW503302 Portugieser Perpetual Calendar uses Cal. 52610 (IWC in-house perpetual calendar with 7-day power reserve). The perpetual calendar is displayed through four aperture windows at 12, 3, 6, and 9. This is a technically complex reference and the most expensive standard Portugieser.

Known reproduction risks

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HIGH RISK

Replica Portugieser Perpetual Calendars with non-functional perpetual calendar mechanisms

  • The four aperture windows on replicas are often printed discs rather than functioning mechanical calendar modules; they do not track dates correctly
  • Exhibition caseback on replicas typically shows a simple automatic movement with an ETA rotor, not the Cal. 52610 architecture
  • The 7-day power reserve is not reproduced on replicas; the watch will stop within 48 hours if wound fully
  • Applied Arabic numerals and blued hands on replicas fail close inspection at magnification

The Portugieser Perpetual Calendar is among the most complex and highest-value IWC references. Any purchase should include an IWC service receipt or recent IWC inspection documentation.

Dial variants by era

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EraDescriptionIdentifiers
2003 to presentWhite or silver dial with four aperture windows displaying day at 12, date at 3, month at 6, and leap year indicator and small seconds at 9. Blued steel hands and applied Arabic numerals.
  • Four aperture windows in a symmetrical layout at 12, 3, 6, and 9
  • Day at 12, date at 3, month at 6, leap year + small seconds at 9
  • "PORTUGIESER PERPETUAL CALENDAR" text below the crown hallmark
  • Blued steel hands with fine arrowhead tips
  • Power reserve indicator on caseback or integrated into the movement (visible through caseback)

Service part flags

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Perpetual calendar displays

Original: The four aperture windows should display the correct perpetual calendar date at all times; the mechanism automatically accounts for month lengths and leap years without manual correction through 2100.

Replacement tells
  • A calendar display that requires correction for short months; a correctly functioning perpetual calendar does not need correction
  • Aperture windows showing the wrong sequential order compared to the known factory layout (day/date/month/leap)
  • Any annual calendar or simple date mechanism in place of the perpetual calendar

Case back markings

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2003 to present
  • Exhibition caseback showing Cal. 52610
  • Engraved ring: IWC SCHAFFHAUSEN with reference IW503302 and serial
  • The 7-day power reserve display is visible through the caseback as a sector indicator
  • No soft iron cage (Portugieser family)

Movement tells

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  • Cal. 52610 is a 7-day manual-wind perpetual calendar caliber. There is no automatic rotor; the movement visible through the caseback should show no rotor.
  • If the perpetual calendar mechanism is damaged, the calendar will begin to mistrack. Verify the date tracking is correct for the current calendar month and year before purchase.
  • Power reserve at 7 days is verified by winding the watch fully and tracking the days until it stops.
Sources: IWC Portugieser Perpetual Calendar page; WatchUSeek -- IW503302 Perpetual Calendar thread.

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