If you were curious about the differences in the dial and caseback of these two watches read on.
SKX007K has no "21 jewels" on the dial and the sub dial text says: "7S26- 002R R 2"
SKX007J has the "21 jewels" on the dial and the sub dial text says: "MADE IN JAPAN 7S26-002L R 2"
SKX007K has no "Japan A" to the left of the serial number. Clockwise from the serial number it reads: "Serial number A Stainless Steel SEIKO 7S26-0020 AO (in a box) SCUBA DIVER'S"
SKX007J has the "Japan A" to the left of the serial number. Clockwise from the serial number it reads: "Serial number JAPAN A Stainless Steel SEIKO 7S26-0020 A0 (in a box) SCUBA DIVER'S"
These are the differences between the two watches. Everything else is the same.
So, differences are:
Exact same parts in:
Case and everything else
There has been much discussion over the years about these two watches (along with the SKX009K/J and SKX011J/K) as to whether one is "better" than the other etc. The consensus is that they are the same watch except for the different dial and caseback. Now is the SKX007J actually made in Japan while the "K" comes from Singapore (or now Milaysia?). According to Seiko the "J" is marked differently for different markets. From the SCWF Dive Reference:
"There has been extended discussion among Seiko diver collectors on the differences between SKX007J and SKX007K. The SKX007J has extra text on the dial that's not on the SKX007K -- "21 JEWELS" under "DIVER'S 200m" and in small lettering "Made in Japan" along bottom edge of dial below 6 o'clock. Some people have said the SKX007J is made in Japan and the SKX007K is made in Singapore and the Japan-made model seems to be better. Others argue there's no proof of the country of manufacture or of any difference in quality between the divers. Many people on the S&C Forum have concluded that there is only cosmetic but no real difference between the J and the K variations -- they are all great divers.
In answer to the question, "What are the differences between SKX007J and SKX007K?," Seiko Japan said: "The watch ref.#SKX007J and SKX007K are completely same watch model. The shipping route is slightly different. We are not able to inform you of the details" (email from Seiko Japan Service Group, 10/28/02). "
Even if the "J" is made in Japan and the "K" is made in Milaysia (now in Milaysia; used to be Singapore) the machines and robots that make the movements and watches would be the same in either country so the techniques and procedures would be the same regardless of where the actual watch is produced.
So, if you just have to buy a watch that says "Made in Japan" on it the SKX007/09/011 is for you. If you want identical quality and want to save a few $ then the "K" variant is for you. Personally I wear the SKX007K more than the "J" as I like the cleaner look better. This is purely a subjective thing and as they say: "your milleage may vary".
I hope that this helps...