If you thought the Machin series was the ultimate in terms of the number of varieties there are to collect, you might need to think again. Its myriad perforation types make the 1906 Landscapes definitive series of Bosnia & Herzegovina a serious rival.
Moreover, the stamps are stunners, at the time of their issue heralded by many as the most beautiful stamps in the world.

Bosnia & Herzegovina was a former enclave of the Ottoman Turkish empire which by the late 19th century was under Austrian administration. Its first pictorial stamps were designed by Koloman Moser, who was also responsible for many fine issues of Austria-Hungary.
The basic set comprised 16 values from 1-heller up to 5-kreuzer, each with a different design in one of two different formats. Most of these were scenic views, although some values showed modes of postal transport and the top value bore a portrait of the Austrian Emperor Franz Josef I.
The stamps were finely engraved with elaborate frames, but that is not the only reason why they have always been very popular with collectors. It is the hunt for the various perforation varieties that makes them so alluring.
The majority of printings were    line-perforated 12½ and 9¼, but you can also find examples perforated 5¼, 6½, 10½, 11½ and 13½, and stamps which are imperforate. And that’s not all. There are also compound perfs to be found, where a stamp has two or even three of the different types.
Add up all these permutations, you will need to find almost 2,500 varieties to complete a collection of all possible types of all values! Needless to say, it is thought that no-one has yet managed to do this!

The reason behind this perforation bonanza is not known. One theory has it that a print order which laid down that any perf type could be deployed was misinterpreted as meaning that every type should be deployed. Other stories suggest that managers of printing companies produced variations to order.
What is certain is that all these varieties were available from post offices and were postally used, so   they cannot be dismissed as mere philatelic fabrications.
Even the rare perf 13½, which is regarded as a proof form, and the ultra rare perf 5¼ can be found on stamps sold over the counter and used.
Rarest of all is perf 11½, a privately produced perforation by the monks of the Marija Zvijezda monastery in Banja Luka, only found used.
None of the rarer varieties should be bought without a certificate of authenticity, as forgeries made from imperforate copies abound.

Should you not want to spend the rest of your life looking for perf variations, there are still plenty of other ways to enjoy the Landscapes series. Much of the proof material is on the philatelic market, and there are varieties that don’t involve perforations.
In 1910, the entire set was reissued with an extra border bearing the text ‘1830-1910’, to mark the Emperor’s 80th birthday. Three new values in the original format were added in 1912, although the whole set would be invalidated at the end of that year.
In 1914 and 1915, remaining stocks of various values were overprinted with the date and a surcharge to aid the war effort – World War I having been sparked by an assassination in Bosnia, of course – and in 1918 the remaining 2h stamps were reintroduced again because of a shortage of that particular value, again with a date overprint.
After the war, a few values were even overprinted for use in the new nation of Yugoslavia, of which Bosnia & Herzegovina was now part.