Every item offered at auction is assigned a lot number. The number is sequential within the sale, prints on the auction catalogue, displays on the saleroom screen as the auctioneer takes bids, and persists on the invoice and condition documents after the hammer falls. Lot numbers are the indexing system through which the entire sale is run.

How lot order is set

Cataloguing departments choreograph lot order with care. Marquee jewels are placed at points in the sale where bidder energy is highest, typically the front third for evening sales and at well-spaced intervals across the running order to maintain pace. Lot order is not strictly chronological by period nor strictly hierarchical by value; it is theatrical, designed to maintain rhythm in the saleroom and on the live auction feed.

Practical use

Buyers register a paddle against a buyer account, then bid by lot number on each piece they pursue. After the sale, the lot number is the reference under which the auction house issues the invoice, packs the goods, and books any post-sale changes such as condition appeals. Where a piece is later resold at the same house, an internal cross-reference often links the new lot number to the prior one, which is why provenance research often begins with prior lot numbers in old catalogues held by the major houses' archives.

Renumbering and withdrawn lots

If a lot is withdrawn before the sale, its number is normally left vacant rather than re-used, and the auctioneer announces 'lot X has been withdrawn' before moving to the next number. Late additions appear with letter suffixes (e.g., lot 47A) so that the printed catalogue numbering remains stable.