{"document_id":"BLC-STUDY-0141","slug":"lamport-clocks","title":"Time, Clocks, and the Ordering of Events in a Distributed System","authors":"Leslie Lamport","year":1978,"date_label":"1978","publisher":"Leslie Lamport","paper_type":"Design paper","category":"Consensus","topics":["Consensus"],"source_url":"https://lamport.azurewebsites.net/pubs/time-clocks.pdf","source_label":"Lamport","legacy_pdf_path":null,"sha256":null,"sha256_note":"No hash is published. This build does not store those PDF bytes, so a checksum would be invented. Where a legacy path exists, it points at the Internet Archive copy of the old library.","version":"Source cited by the 1978 study. The study is the reading. This page does not add a second essay.","doi":null,"rights_status":"Official external source only","source_status":"Official source","use_status":"Metadata and commentary only. The reading is the study page.","licence":null,"licence_label":"No licence recorded. Rights status under review.","full_text":null,"full_text_reason":"Full text is not published on this page. Public availability is not a licence to republish a document. Blockchain Lab has not recorded a licence that permits an HTML transcription, a training set, or a retrieval corpus of the paper. Text on this page is Blockchain Lab's own wording, or a pointer to a study that is also Blockchain Lab's wording.","editorial_line":"Lamport clocks number events so that if A happened before B, A's number is smaller. The converse is not true. That one direction is the whole idea.","canonical_url":"https://blockchainlab.com/whitepaper/lamport-clocks","record_url":"https://blockchainlab.com/research/corpus/papers/lamport-clocks","study_url":"https://blockchainlab.com/whitepaper/lamport-clocks","last_reviewed":"2026-10-01","last_checked":"2026-10-01","relationships":[{"rel":"Canonical reading","label":"Lamport clocks study","href":"/whitepaper/lamport-clocks"},{"rel":"Related paper","label":"Paxos","href":"/whitepaper/paxos"},{"rel":"Related paper","label":"Raft","href":"/whitepaper/raft"}]}