Historical clue formulations

• Rock climber's notch — 2024-07-23
• Initial progress — 2017-10-11
• Starting progress, metaphorically — 2016-08-17
• It can aid one's climb to the top — 2007-05-26
• Initial progress — 2006-08-27
• Initial progress on a tough problem — 2004-10-04
• Early progress — 2004-01-04
• Initial advantage — 2003-05-24
• Slight support — 2001-05-19
• Initial gain — 1998-05-07