Current artwork numbers are based on the catalogue numbers first assigned to objects in The Sculpture of Isamu Noguchi, 1924–1979: A Catalogue by Nancy Grove and Diane Botnick (Garland, 1980), originally 1–820, and ordered chronologically. Artworks created after the publication of the Grove/Botnick catalogue are assigned a number above 820. Sculptures discovered after the publication of Grove/Botnick, but dated prior to 1979, are generally incorporated into the standing chronological order by the assignment of an existing number with the addition of the suffix “.01,” “.02,” “.03,” etc. For example no. 135 is a portrait work dating from 1934 that was included in Grove/Botnick, while no. 135.01, also a portrait work dating from 1934, was identified after the publication of Grove/Botnick.
Artwork entries are generally ordered chronologically by the year the work was begun; within each year artworks may be ordered according to material, subject, or style. Exceptions to this ordering include drawings, models, and select sculptures that were not included in Grove/Botnick and were catalogued en masse following Noguchi’s death. These artworks are assigned numbers between 2,000 and 9,000, irrespective of date. For example, drawings in the collection of The Isamu Noguchi Foundation inventories in the 1990s were assigned sequential numbers beginning with 7,000. Additionally, artworks for which new date information has emerged since 1980 maintain their original number and place in the order.
Artworks that are directly related share a number followed by an alphabetical or numerical suffix, and are grouped together chronologically with the primary or earliest known example in the series. For example, no. 498 is assigned to a 1962 balsa wood sculpture, which was cast in bronze editions between 1962 and 1988, nos. 498B-1/8, 498B-2/8, etc. The letters A, B, C, etc., denote different versions in style or materials; fractions identify edition series numbers (e.g., 1/3 means 1 of 3); lowercase letters often denote a classification, such as “m” for models; numbers after a dash are assigned to relational elements of a whole. For example, while no. 139 is a complete dance set, nos. 139-1 and 139-2 are the two elements that make up the set.