Grand Seiko 61GS complete guide

The 61GS family, developed by Suwa Seikosha, has the largest number of models in the vintage Grand Seiko range, with a great variety of designs, and only a few of them following Taro Tanaka’s “Grammar of Design” rules.

In terms of accuracy, the 61GS family movements can be divided into three groups:

• Calibers 6145A and 6146A were regulated within the parameters of the Grand Seiko Standard, which at the time was +5 to -3 seconds per day
• Calibers 6155A and 6156A were defined Special and they were regulated to be accurate within +/-3 seconds per day
• Calibers 6185A, 6185B and 6186B were Very Fine Adjusted (V.F.A.) with an unprecedented accuracy of +/-2 seconds per day

All of the 61GS automatic movements can be wound manually and have a hacking function, and they all have a date or day/date complication.

61GS Date with caliber 6145

The 61GS caliber 6145, introduced in 1968 (production started in 1967), was the first Japanese automatic movement running at 36,000 bph.

61GS Day-Date with caliber 6146

The 6146 caliber is the day/date version of the 6145.

61GS Special Date with caliber 6155

Introduced in late 1970, the Grand Seiko 61GS Special boasted an accuracy of +/-3 seconds per day. The 6155 caliber is even more “Special”, because it was only used for a single reference.

61GS Special Day-Date with caliber 6156

Grand Seiko caliber 6156 is the day/date version of the 6155. Unlike the 6155, this movement was featured in a variety of models.

61GS V.F.A. Date with caliber 6185

The Grand Seiko V.F.A. (Very Fine Adjusted) watches, introduced in 1970, were guaranteed to be accurate to within one minute per month, at least for the first two years of ownership.

For a mechanical automatic watch, an accuracy of +/-2 seconds per day was unprecedented, and is still astonishing even by today’s standards.

61GS V.F.A. Day-Date with caliber 6186

Grand Seiko caliber 6186 is the day/date version of the 6185.

61GS Movements

Caliber 6145A

Technical sheet

Type	Automatic
Complications	Date
Bph	36,000
Jewels	25
Accuracy	+5 to -3 seconds per day
Manual wind	Yes
Hacking	Yes

Caliber 6146A

Technical sheet

Type	Automatic
Complications	Day/Date
Bph	36,000
Jewels	25
Accuracy	+5 to -3 seconds per day
Manual wind	Yes
Hacking	Yes

Caliber 6155A (Special)

Technical sheet

Type	Automatic
Complications	Date
Bph	36,000
Jewels	25
Accuracy	+/-3 seconds per day
Manual wind	Yes
Hacking	Yes

Caliber 6156A (Special)

Technical sheet

Type	Automatic
Complications	Day/Date
Bph	36,000
Jewels	25
Accuracy	+/-3 seconds per day
Manual wind	Yes
Hacking	Yes

Caliber 6185A and 6185B (V.F.A.)

Type	Automatic
Complications	Date
Bph	36,000
Jewels	25
Accuracy	+/-2 seconds per day
Manual wind	Yes
Hacking	Yes

Caliber 6186B (V.F.A.)

Type	Automatic
Complications	Day/Date
Bph	36,000
Jewels	25
Accuracy	+/-2 seconds per day
Manual wind	Yes
Hacking	Yes