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Authored by Tokunaga / Randall Benson


Dear Tokunaga-san

I woudl like to know what years the 6306-7000/7001 diver was produced, and how that affected the 6309-7040/7049 diver. Where both watches bbeing produced durring the same years, and which one came first, the 6306, or the 6309.

I have always though the 6306 21 jewel came first, but I seek your advise on this.

Thank you.
Randall Benson


Dear Randall-san:

I designed these models from 1975, as the next model of 6159 600m professional diver's watch. So if I am allowed to judge this history from my memory and my saved stuff, it will be as follows.

Both of the 6306 diver's watches for domestic and the 6309 diver's watches for overseas were made in Suwa Seikosha from 1976, and 6306 diver's watches were put on the production "slightly first". Those basic specifications were same except for the number of jewels and the bilingual language display of the calendar.

The reason why I said the "slightly first" is only that I was not able to confirm the start month on the production. I am sure the 6306 diver's watches came first, too.

If speaking from the viewpoint of plans or of technical designing on 6306/6309 diver's series, I am sure the concept of influence or of derivation between those watches did not exist in 1976. It is because I issued the specification drawing of those diver's watches as the same one. This means that I wrote only a description such as "6306 ( Japan ) / 6309 ( Overseas )" on one sheet of common paper in order to show the difference. The drawing below is the original specification drawing of 6306/6309 150m diver's watch (which has been editted).

Incidentally, as for those calibers, the 6309 caliber was designed first. The base caliber of 63 series (about ten) is 6309.

I hope this helps you.

Sincerely yours,

Ikuo Tokunaga

The original specification drawing of 6306/6309 150m diver's watch.

6309 150m diver's watch (From Seiko catalog)


6306 150m diver's watch (From Seiko catalog)

Ikuo Tokunaga[/b]
Picture credit: [b]Seiko[/b]
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