At the time of writing, I've been unable to establish in which half yearly Seiko JDM catalogue the 7A36 Surf Timers first appeared, which I consider a prerequisite for starting this post.

I've scrolled through the scans of 1985 and 1986 JDM catalogues hosted on SCWF and strangely there's no sign of them. All examples seen to date have had 54xxxx or 55xxxx prefix case-back serial numbers, indicating manufacturing dates of April and May 1985. From the few price tags seen in photos of NOS examples, their recommended retail price was 35,000 Yen.
According to this screen print of a search result on '7A36' I took off Seiko Oceania's database, more years ago than I care to remember, there were
theoretically 4 variants of 7A36-xxxx. That said, I know for a fact there were only
three. It's conceivable that a 7A36-
701A (as opposed to 7A36-
7A10 as shown) may have been planned, but was never productized. A somewhat incongruous sales code of SEJ027, completely different dial code 7A20X914 (compared to the other 7A36 Surf Timers' 700L prefixed dials) and other missing data fields points to it having been a keying input error (
viz. 7T36).

- 7A36-7xxx Variations.JPG (103.54 KiB) Viewed 11950 times
Note the dial colour for the 7A36-7000 (S)SKP019 is erroneously shown as 'BROWN' (another common recurrent error).
7A36-7000 SKP019.
Black chrome coated watch case with black plastic shroud. Yellow dial with black printing and chronograph hands. Yellow plastic pushers and crown. Black 22mm neoprene rubber strap with yellow keeper and black chrome buckle.
7A36-700A SKP018.
Black chrome coated watch case with a yellow plastic shroud. Black dial with yellow printing and chronograph hands. Black plastic pushers and crown. Yellow 22mm neoprene rubber strap with a black keeper and black chrome buckle.
7A36-7010 SKP012.
Silver anodized watch case with a blue plastic shroud. Light green dial with black printing and blue chronograph hands. Light green plastic pushers and crown. Blue 22mm neoprene rubber strap with green keeper and silver anodized buckle.
All 3 variants have black English / Kanji day and date wheels and use stainless Phillips headed shroud retaining screws.
Here's a few photos of original examples of each variant that I saved over the years.
7A36-7000 SKP019:

- 7A36-7000-Black-YellowFace-SKP019-GMT+9-YahooJapanAuctions-June2011-1.jpg (26.78 KiB) Viewed 11954 times

- 7A36-7000-Black-YellowFace-SKP019-GMT+9-YahooJapanAuctions-June2011-2.jpg (27.34 KiB) Viewed 11954 times

- 7A36-7000-Black-YellowFace-SKP019-GMT+9-YahooJapanAuctions-June2011-3.jpg (35.22 KiB) Viewed 11954 times
7A36-700A SKP018:

- rsz_7a36-700a-yellow-blackface-ebay-may2013.jpg (244.57 KiB) Viewed 11961 times

- 7A36-700A-Yellow-BlackFace-eBay-Nov2013.JPG (113.29 KiB) Viewed 11961 times
7A36-7010 SKP012:

- rsz_7a36-7010-blue-greenface-ebay-nov2012-1.jpg (169.39 KiB) Viewed 11955 times

- rsz_7a36-7010-blue-greenface-ebay-nov2012-2.jpg (244.01 KiB) Viewed 11955 times

- rsz_7a36-7010-blue-greenface-ebay-nov2012-3.jpg (137.39 KiB) Viewed 11955 times

- rsz_7a36-7010-blue-greenface-ebay-nov2012-4.jpg (147.74 KiB) Viewed 11955 times

- rsz_7a36-7010-blue-greenface-ebay-nov2012-5.jpg (217.5 KiB) Viewed 11955 times

- rsz_7a36-7010-blue-greenface-ebay-nov2012-6.jpg (164.66 KiB) Viewed 11955 times
Judging by the proportions of 7A36 photos I've saved in my folder (regardless of their condition), it suggests that the black / yellow 7A36-7000 SKP019 was by some margin the commonest of the three variants. Followed closely by the blue / green 7A36-7010 SKP012 and that the yellow / black 7A36-700A SKP018 was by far the scarcest of the three.
Regular problems seen with used examples include: split plastic shrouds (usually at the screw fixings); cracked plastic pusher buttons and crowns and broken or perished straps (frequently replaced with another rubber or leather strap).