The Seiko 8123A is a classic quartz analog movement renowned for its simplicity, reliability, and accurate timekeeping. Developed during the late 20th century, this caliber was widely used in many Seiko watches designed for everyday wear. It combines Seiko’s robust quartz technology with a straightforward analog display featuring time and date functions. The 8123A remains a well-regarded movement for its long battery life and low maintenance requirements.

Technical Specifications

• Caliber Number: 8123A

• Movement Type: Quartz (Analog)

• Display:

  • Hours, minutes, seconds hands

  • Date window (usually located at 3 o’clock)

• Accuracy: Approximately ±20 seconds per month

• Battery Type: SR927W (1.55V silver oxide)

• Battery Life: Typically 2 to 3 years

• Jewels: None (electronic movement)

• Crown Positions:

  • Position 0: Normal operation

  • Position 1: Date adjustment

  • Position 2: Time adjustment

Key Features

Accurate Timekeeping

The 8123A movement provides reliable and consistent timekeeping, powered by a quartz crystal oscillator that ensures a stable frequency and low deviation. Users can expect accuracy within approximately 20 seconds per month, suitable for daily wear.

Date Functionality

A date window is incorporated into the dial, typically at the 3 o’clock position, displaying the current date for convenience. The date is quick-settable through the crown to allow easy adjustment.

Energy Efficient

The movement uses a standard SR927W silver oxide battery, providing a typical lifespan of two to three years. This efficient power consumption allows for extended use without frequent battery changes.

Operating Instructions

Time Setting

1. Pull the crown out to the second click (Position 2).

2. Rotate the crown clockwise or counterclockwise to set the hour and minute hands to the desired time.

3. Push the crown back in to Position 0 to resume normal operation.

Date Setting

1. Pull the crown to the first click (Position 1).

2. Rotate the crown clockwise to advance the date to the correct day.

3. Avoid adjusting the date manually between 9 PM and 2 AM to prevent damage to the date-change mechanism.

4. Push the crown back to Position 0 after adjustment.

Battery Replacement and Maintenance

• The 8123A requires an SR927W silver oxide battery.

• Battery life averages 2 to 3 years, depending on usage conditions.

• Battery replacement should be conducted by a professional to maintain water resistance and proper sealing.

• No reset procedure is typically required after battery replacement; however, setting the time and date will be necessary.

Maintenance Recommendations

• The movement is fully electronic, requiring no mechanical lubrication.

• Exposure to strong magnetic fields, shocks, and extreme temperatures should be avoided to preserve accuracy and longevity.

• Regular cleaning of the watch exterior helps maintain its appearance and water resistance.

• Water-resistant models should be pressure-tested annually, especially if frequently exposed to water.

Watches Using the Seiko 8123A

The 8123A was commonly used in Seiko’s:

• Entry-level to mid-range quartz watches throughout the 1980s and 1990s.

• Models emphasizing practical, no-nonsense timekeeping with date display.

• Watches with classic, simple dial designs focusing on readability and reliability.

Summary Table

Conclusion

The Seiko 8123A quartz movement stands as a testament to Seiko’s enduring dedication to quality, simplicity, and accuracy. With its straightforward time and date functions, long battery life, and dependable quartz precision, it offers a reliable foundation for everyday watches. Although it lacks advanced complications, the 8123A excels in delivering consistent performance with minimal maintenance, making it a favored choice for classic and practical timepieces.