We are often approached by customers that need help identifying what edition their Base Set Pokemon cards are, or indeed whether their cards are base set or another edition, so we have written this guide to help people work out what edition of Base Set they have.
Identifying Base Set Cards

Base Set was the first Pokemon set printed. It was first released on 20th October 1996 in Japan, then 9th January 1999 in English and the rest of the world.
There are two main ways to identify a Base Set card. Firstly it has no set symbol, see image. Secondly, Base Set contains 102 cards so the card number in the bottom right will always be a "number of 102", for example 47/102 for this Diglett, see image.
Different Base Set Editions
In English language there are four main editions, details of how to identify each can be found below.
1st Edition

Once you know what you are looking for, 1st edition cards are easily identified by the 1st edition stamp about 5mm across made up of a circle with a 1 in the middle with the word edition above. This appears just outside the bottom left corner of the card image, this is circled & magnified on this 1st Edition Charizard.
Shadowless Edition

Shadowless cards are from the first printing after base set. They are known as shadowless as, unlike Unlimited Edition, they do not have a drop-shadow on the card image. On Unlimited cards this can be seen as a darker area to the bottom and left of the card image. The area where the drop shadow is absent is highlight on this Dugtrio to the right.
Energy don't have images on them so to identify shadowless Energy cards you need to look at the copyright information at the very bottom of the card and the first run of dates will read 1995, 96, 98, 99. Rather unintuitively unlimited, which came later, only has 1995, 96, 98 in the first run of dates in the copyright information.
Unlimited Edition

Unlimited cards are those from all printings between Shadowless and UK Print and as a result they are by far the most numerous. As mentioned above Unlimited cards differ from Shadowless in that they have a drop-shadow to the bottom and right of the card image. This can be seen on the Diglett to the right.
UK Print (4th Print /8th Print / Base Set 2000) Edition

UK Print, also known as 4th Print to distinguish it from the three versions above, 8th Print as it was actually the 8th print run, or Base Set 2000 as it was printed in the year 2000.
This was the final and smallest Pokemon print run and was originally believed to mainly be distributed in the UK but was also distributed in Australia and the USA.
UK print cards can be identified by the by the last date in the copyright information being 1999-2000, this is found at the very bottom right corner of the card. Regular Unlimited cards only have 1999 at the end of the copyright information. On UK Print cards the full copyright data reads ©1995, 96, 98 Nintendo, Creatures, GAMEFREAK, ©1999-2000.