Vintage Grand Seiko 56GS Hi-Beat Day-Date (Ref. 5646-5010) Buying Guide

When you think Grand Seiko, you probably imagine a clean round dial, restrained case, and the sort of understated elegance that whispers “I have excellent taste and possibly a well-watered bonsai at home.”

The 5646-5010, however, had other ideas. Released in the early 1970s, this Hi-Beat Day-Date ditched the round case in favor of a TV screen shape — a squarish cushion that looked straight out of a space-age interior design catalogue.

It was part of the broader 56GS family, which housed the 5645 (date only) and 5646 (day-date) calibres. These were the final fully mechanical Grand Seikos of the era before the quartz revolution sucker-punched the industry.

The Specs (a.k.a. Why This Watch Still Deserves Respect)

• Case: Stainless steel TV-style, ~37mm wide (wears chunkier thanks to its square stance)

• Movement: Grand Seiko Cal. 5646, Hi-Beat 28,800 bph, automatic, with hacking and hand-wind

• Accuracy (when new): ±3 to ±5 seconds per day — easily still achievable after a good service

• Crystal: Flat Hardlex mineral

• Dial: Brushed silver or grey with applied baton markers, framed day-date window at 3 o’clock

• Water Resistance: "Splash resistant" by modern standards — don’t even think about swimming

Why It’s Unusual (and Why You’ll Either Love or Hate It)

The 56GS TV Dial sticks out like a polyester shirt at a black-tie dinner. It’s bold, unapologetically 1970s, and a clear attempt by Seiko to modernise Grand Seiko for a younger, style-conscious crowd.

It also reflects a rare moment when GS wasn’t afraid to bend its “Grammar of Design” rules — those carefully engineered angles and reflections were traded for chunky curves and a bold wrist presence.

🔍 Collector’s Tips

1. Dial Condition is King 👑 — Moisture damage ruins value fast. Look for clean, even brushing.

2. Service History Matters 🛠 — Hi-Beat movements wear faster without maintenance.

3. Original Bracelet Bonus 🔗 — Fitted flat-link bracelet adds value.

4. Kanji Day Wheels 🇯🇵 — Quirkier, more desirable to some collectors.

5. Avoid Over-Polishing 🚫 — The TV case’s edges and curves vanish if overly buffed.

💰 Price Guide (2025)

• Mint / Near NOS: £1,200–£1,500 🌟

• Excellent: £800–£1,100 ✅

• Good / Wearable: £500–£750 👍

• Project Watch: £300–£450 🛠

Final Thoughts

The 5646-5010 is the watch you wear when you want people to know you collect Grand Seikos, not just wear them. It’s the model that says, “Yes, I appreciate timeless design, but I also appreciate a good bit of funky 1970s casework.”

Prices have been creeping up in recent years as collectors hunt for quirkier GS references, and the fact that it’s part of the last fully mechanical GS lineup gives it a little extra sparkle.

If you see one in great condition, don’t hesitate too long — because unlike a vintage 3180, you won’t see ten more at the next watch meet.