Seiko 5722B – Technical Guide

Introduction

The Seiko 5722B is a manual-winding mechanical movement, introduced in the mid-1960s and used in early Grand Seiko Chronometer models. It is the successor to the 5722A, featuring minor but meaningful upgrades, particularly in the calendar mechanism. Manufactured by Suwa Seikosha, the 5722B continues the legacy of Seiko’s pursuit of precision, durability, and understated design — all core values of the Grand Seiko philosophy.

It powered several references of the Grand Seiko 5722-9990 and 5722-9970, and is easily recognized by its single date display, chronometer regulation, and pusher-based quickset system.

Technical Specifications

Movement Features

Manual-Winding System

• Wound via the crown at 3 o’clock.

• Delivers a smooth, efficient wind with approximately 30 full turns needed for a full power reserve (~45 hours).

• Built on a robust baseplate architecture adapted from the 5700 series.

Chronometer Regulation

• Factory-adjusted to chronometer standards in multiple positions.

• Early models proudly feature “Chronometer Officially Certified” on the dial.

• In later years, Seiko voluntarily withdrew from Swiss COSC certification and developed its own stricter internal Grand Seiko Standard.

Date Mechanism (Improved Over 5722A)

• Quickset date operated via a pusher at 2 o’clock.

• The 5722B uses a more robust jumper spring and refined cam profile for smoother operation and less wear.

• Date advances automatically at midnight via a semi-instantaneous switch.

⚠️ Avoid pressing the quickset pusher between 10 PM and 2 AM, when the automatic date change is engaged.

Differences Between 5722A and 5722B

Servicing and Maintenance

Lubrication Points

• Escape wheel and pallet fork pivots

• Center wheel and third wheel

• Balance staff (Diashock shock absorber system)

• Date jumper spring and pusher cam

• Keyless works and ratchet wheel

Use high-grade synthetic lubricants. Do not over-lubricate the date pusher mechanism.

Common Wear Areas

Identifying Watches with 5722B

The 5722B movement was fitted into later production runs of Grand Seiko references:

Grand Seiko Models:

• 5722-9990

  • Silver or sunburst dial

  • Applied GS logo

  • Dolphin or lion medallion caseback

  • Chronometer marking (early models)

• 5722-9970

  • Slightly slimmer lugs and case profile

  • Similar dial layout

  • Often came with Grand Seiko-signed crown and buckle

Caseback:

• “5722-xxxx” engraved

• Some casebacks include “Waterproof” or “Water Resistant”, depending on production year

• “Seiko Chronometer” or “Grand Seiko” logos with GS medallion

Summary Table

Conclusion

The Seiko 5722B is a classic, collectible, and historically important Grand Seiko movement. Representing the last manually wound chronometer from Seiko's early golden age, the 5722B combines clean engineering, elegant finishing, and mechanical reliability. The improvements over the 5722A — particularly in the date mechanism — make it a sought-after caliber for vintage enthusiasts and serious restorers.

Today, any Grand Seiko powered by the 5722B is seen not only as a precision timepiece but also as a symbol of Seiko’s pursuit of horological excellence during the 1960s.