Is there a dichotomous key available for looking up LEGO pieces by progressively answering information about their characteristics? It doesn't necessarily need to fit the strict definition of a dichotomous key (namely there being only two choices per stage of identification).

For example:

  • Does it have studs? Yes
  • How many sides have studs? 2
  • How many studs are there total? 6
  • What color is the piece? Gray

might yield part number 4277927

rendering of part 4277927

Additional characteristics such as estimated date of manufacture or whether a piece is counterfeit may be discerned by applying the same method to non-functional features such as the font of the logo.

  • 4
    s/bump/stud/G :) But I like this idea.
    – gev
    Commented Jan 10, 2016 at 10:27
  • Sounds like we have a volunteer.
    – user3971
    Commented Jan 13, 2016 at 1:36
  • Not quite (although it would be a fun project... :-)
    – ebpa
    Commented Jan 15, 2016 at 22:49

1 Answer 1


Closest thing that I know of is the peeron site - you can use google to search only peeron by adding "site:peeron.com" or you can use the peeron website to find the part. Start by looking at the part list for a few sets you have (or see for sale) and then when you get used to the terminology you should know how to search for the unknown part. It lists all sets/years that the part came from, and all colors it is available in, and uses Lego part numbers and set numbers (it ads an extra digit to set numbers that have been reused by Lego)

brickwiki says:

Peeron is a set database with set inventories and an instruction scan repository (PICSL1) run by Dan Boger, with the help of a number of volunteers (Clark Stephens, TWS Garrison and a number of developers).

[ . . . ]

Peeron is one of the three major sources (with BrickLink and LDraw.org) for nomenclature and classification, it maintains a color list, and assigns (in cooperation with LDraw) names and numbers for parts that haven't yet been named.

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