Seiko 5C23A Technical Guide

Overview

The Seiko 5C23A is a high-precision quartz analog movement from the 5C family, introduced by Seiko in the late 1990s to early 2000s. It builds upon the architecture of the 5C20A, offering the same slim profile but with the added convenience of a date display. Designed for refined dress watches and minimalist daily wearers, this movement reflects Seiko’s continuous commitment to quartz craftsmanship during a period of market evolution.

With its ultra-thin design, hacking feature, and user-friendly date function, the 5C23A offers an elegant balance of form and function in quartz timekeeping.

Technical Specifications

• Caliber: Seiko 5C23A

• Movement Type: Quartz analog

• Jewels: 2

• Functions: Hour, minute, central seconds, date

• Accuracy: ±20 seconds per month

• Battery Type: SR920SW (1.5V silver oxide)

• Battery Life: Approx. 3 years

• Hacking Seconds: Yes (seconds hand stops when crown is pulled out)

• Quickset Date: Yes (via crown rotation)

• No Day Function

• Manual Reset (Zero Positioning): Yes

• Movement Diameter: ~23.5 mm

• Movement Thickness: ~2.8 mm

• Integrated Circuit: CMOS-based, quartz oscillator regulated

• Temperature Compensation: No (standard crystal regulation)

Movement Features

Slim Profile with Full Functionality

Despite the added date complication, the 5C23A remains impressively slim, increasing case design flexibility for Seiko’s dressier and refined quartz models. It enabled watches with thin profiles and minimalist aesthetics, popular during the late ‘90s and early 2000s.

Jewel Placement

The movement contains 2 synthetic ruby jewels, placed at critical pivot points such as the gear train or step rotor, helping reduce wear and maintain smooth motion over years of use. These jewels support durability in long-term daily wear.

Hacking and Hand Alignment

• The hacking seconds feature allows the user to stop the seconds hand when the crown is pulled out—an essential feature for precision time setting.

• The manual hand alignment (zero-reset) function allows realignment of the hour, minute, or seconds hands after a battery replacement or shock. This is triggered via a reset contact point on the movement or by a crown-battery insertion sequence.

Setting Instructions

1. Pull the crown to the first position to set the date (quickset). Rotate the crown clockwise or counterclockwise depending on the model.

2. Pull the crown to the second position to set the time. The seconds hand will stop.

3. Push crown back in to resume normal operation.

⚠️ Avoid changing the date between 9 PM and 3 AM to prevent damage to the calendar mechanism.

Applications and Watch Models

The Seiko 5C23A was used in:

• Seiko minimalist quartz dress watches

• Select Seiko Spirit and Seiko Selection series models

• Refined stainless steel models from the late 1990s to mid-2000s

• Ladies' and unisex slim watches with elegant design codes

Many of these watches featured clean white, black, or champagne dials with applied indices and slim cases—perfect for professional and formal settings.

Servicing Notes

• Battery replacement is straightforward using an SR920SW (1.5V). Always verify polarity and clean contacts before closure.

• Manual reset mode should be activated after battery installation to ensure hand alignment.

• Use non-magnetic tools and anti-static precautions when servicing due to sensitive IC components.

• Replacement parts are rare; movements may need to be swapped from donor watches for repairs.

Conclusion

The Seiko 5C23A is a thoughtfully engineered quartz movement that prioritizes slim form, practical function, and reliability. It fits seamlessly into Seiko’s tradition of producing quality dress watch calibers with long service life and user-friendly features. While it may not boast the prestige of the 9F series, the 5C23A stands as an understated yet dependable choice for anyone seeking minimalist excellence.