Seiko enthusiasts—Help! When did Seiko first release the Baby Tuna, and more specifically, the model that prefigures contemporary Baby Tunas like the SRPH77K (Save the Ocean Baby Tuna Antarctica Penguin)?

wizard903

I've searched far and wide but can't ascertain a definitive answer concerning the original year that Seiko produced what we enthusiasts have to come to refer to as the Baby Tuna. 

This article seems to suggest 2015, which seems much too late, whereas this article suggests the reference 7549-7010. Help!

In addition to this general question about the Baby Tuna's origin, I'm also interested in another, more specific question that may have a different answer:

What specific model prefigures contemporary Baby Tunas like the SRPH77K (Save the Ocean Baby Tuna Antarctica Penguin)?

I'd appreciate any insight y'all have to offer. 🙏

#seiko #seikodiver #tuna #seikoprospex #help
Reply
SurferJohn
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It was definitely after 2010.  A look at the serial numbers on observed pieces will give you the answer.  The first digit of the serial number being the year of manufacture.

wizard903
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SurferJohn

It was definitely after 2010.  A look at the serial numbers on observed pieces will give you the answer.  The first digit of the serial number being the year of manufacture.

Thanks John—will do. That said, do you have any idea what is generally considered to be the first Baby Tuna?

SurferJohn
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Not exactly sure, I think there was at least one before the Solar Tuna.  I sent my Solar Tuna away when I got an Arnie.

wizard903
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Update: This article claims that Baby Tunas originated with models that employed the 5M23 Kinetic movement, which was manufactured between 1998 and 1999, and that had 200M of water resistance. In contrast, another article mentions reference 7549-7010 as an example of a Baby Tuna; but the former article convincingly distinguishes between reference 7549-7010, which it refers to as the Golden Tuna, and the smaller 4mm smaller, 43mm case diameter and 200M water resistance AGS and Kinetic drive models.

Thus it seems that, while the specific origin of the phrase "Baby Tuna" applies to those particular Kinetic references, in practice the phrases "Baby Tuna" and "Mini Tuna" are used loosely (and ambiguously) by the community to refer to any model that has the "tuna can" shape and shroud but is smaller than typical Tunas.

Indeed, the phrase "Mini Tuna," as distinct from "Baby Tuna," appears to originate in 1986 from reference 7C46-6020 SBBN009. 

Also from the article:

The Baby Tuna 5M23A had two variations: the 5M23-6A19 (Kinetic Quartz) and the 5M23-6A10 (AGS) . . . . For the Baby Tuna 5M23, both [shrouds] were made of plastic . . . . The youngest of the [Tuna] series, Baby Tunas (5M23) are also the smallest with a 43-mm diameter . . . . It is not clear exactly who manufactured the 7C46 and 5M23A movements of the re-issued Golden Tuna and the Baby Tuna, but it was most likely Suwa . . . . Finally, the Baby Tuna 5M23 has “Kinetic Quartz” in the dial . . . . Similar to the Golden Tuna 7C46, the Baby Tuna 5M23 also uses a train wheel setting device and a step motor driving system, which is basically a load-compensated driving pulse type. What sets apart this movement from the rest of the Seiko Tuna watches, however, is its automatic generating system and power reserve indicator.