Most of my research was done using Peeron, using their large collection of catalogue scans, so many thanks to them and to all who sent Peeron their scans. All the images are also from Peeron.
The early phase
The earliest sets that I could trace dating from the 1950s were numbered in the 700 series, with accessories and small vehicles (not brick-built) in the 1200s. I presume even earlier sets and wooden toys used lower series, but as of now I don’t have much information on those.
In the event, accessories were soon renumbered to the 200 series, and during the 1960s many number series were created for emerging themes: Basic sets using the 000 series, Trains in the 100s, accessories in the 200, 400 and 800 series, regular sets now in the 300 series, and miniature cars in the 600s.
In 1969, the introduction of 12V Trains had them grab the 700 series, while brand new Duplo was assigned the 500 series.
The 1970s were a time of great expansion for LEGO, and many new themes were introduced. Basic sets were now numbered in the 1-99 series (without leading ‘0’ this time) as well as the 200 series. Homemaker sets also used the 200 series, the classic sets as well as the new Legoland sets were numbered in the 300 range, smaller Legoland sets in the 600s, Gears technical sets in the 800s, and accessories in the 900 series.
The Legoland phase
By the end of the 1970s, older 3-digit series had to be recycled in order to fit in all the new sets. New Legoland Town, Fabuland and Scala sets used the (second) 300 series, smaller Town sets used the (second) 600 series, while Legoland Space sets used available 800 and 900 series numbers. But it was obvious that the 3-digit system was nearly exhausted, and duplicating set numbers was likely becoming confusing for TLC.
The System phase
Starting in 1980 most of the new sets were given 4-digit numbers. The Legoland themes were all assigned to the 6000 range (6000s for Castle sets, 6300s for large Town sets, 6600s for smaller ones, 6800s for small Space sets and 6900s for large ones). Within each group, lower set numbers generally indicated smaller sets. Promotional and educational (Dacta) sets were numbered in the 1000s, Duplo in the 2000s, Fabuland in the 3000s, Ships in the 4000s, accessories and Model Team in the 5000s, Trains in the 7000s and Technic in the 8000s. In general, each sub-theme was assigned to a specific 100-number block that it would fill up over time. Meanwhile, Basic sets and some accessories would keep recycling old 3-digit series. This numbering scheme would last for over 15 years without major changes.
During the 1990s, new themes besides the classic System triumvirate of Town-Space-Castle were assigned new number blocks in the same general scheme. For instance, Pirates grabbed the 6200s, Aquazone the 6100s, Time Cruisers shared the 6400s with Paradisa, Wild West used the 6700 series, while Town expanded into the 6400-6500s. Moreover, new themes outside of the System sphere were assigned previously unused series, such as FreeStyle in the 4000s, Computer Games in the 5700s and Belville in the 5800s.
By the late 1990s, the System 6000 range was becoming crowded, so new themes began using number blocks outside of the regular System scheme. For instance, Ninja (Castle) and Insectoids (Space) themes used the 3000 series, Adventurers the 5900s, Rock Raiders the 4900s, and Star Wars licensed sets were given the 7100 series. Dacta also moved to the 9000 series.
Random numbers phase
At some point during the early 2000s, for an unfathomable reason it was decided that assigning number blocks to specific themes was not the way to go anymore. Perhaps this was becoming impractical with the proliferation of short-lifespan themes. In any case, starting slowly circa 2000 and becoming the rule rather than an exception by 2005, new sets were issued numbers randomly in any available range, with little apparent logic. As a consequence, in the same number series one could now find say Duplo, Star Wars and Creator sets. This is the numbering scheme that prevails today, with some exceptions.
Indeed, a few themes or product categories still have specific number blocks. Starting in 2001, Lego Shop exclusives were assigned numbers in the 10000 range. The series include exclusive sets or accessories from any theme in roughly chronological order. In 2007, the 20000 series were issued to Brickmaster magazine gift sets in chronological order. The 21000 series is used for Architecture sets since 2008. Promotional polybags are numbered in the 30000 series since 2009, while seasonal sets use the 40000 series. Lastly, since the early 2000s some value packs have been issued numbers in the 60000 range.
Since 2008, a 6-digit series is in use for special items such as key chains, pens and magnets, generally made in China and not part of the ‘core’ LEGO product range. These products are numbered in the 850000 series.
As if 6-digit numbers were not long enough already, sporadically over the years but more frequently during the late 2000s other special items have been only issued a material ID number, made up of 7 digits. These numbers appear to be issued to everything LEGO: individual bricks, instruction sheets, cardboard boxes, etc. Some special sets only have this material ID number, often in the 4000000 series.
Approximately 70% of the available set numbers in the 1-9999 series has been used at least once, so TLC is not yet in danger of running out of available 4-digit numbers. Moreover, with the recent introduction of 5-, 6- and 7-digit set numbers, TLC should have many centuries worth of set numbers for us to enjoy.
Some random trivia
- Between 1974 and 1979, all Lego sets in the US had a numbering scheme distinct from the European ‘official’ standard. Briefly, Duplo sets were numbered in the 000 series, Basic and Fabuland in the 100 range, Legoland Town and Space in the 400 and 500s, classic sets in the 700s and Expert Builder sets in the 900s.
- Samsonite in Canada also used some distinct number series for their exclusive sets during the 1960s and 1970s, series that sometimes clashed with the ‘official’ numbering scheme.
- Many US-exclusive sets of the early 1980s were obviously forgotten by TLC as their numbers were reused during the 1990s. For instance, 6375 Gas Station (1980) and 6901 Mobile Lab (1980) were recycled for 6375 Trans Air Carrier (1990) and 6901 Space Plane (1998) respectively.
EDIT: Castle=6000 series.
Edited by Fugazi, 11 May 2011 - 01:55 PM.