Historical clue formulations

• Like some liquors — 2026-08-30
• Firm — 2026-08-20
• Like sudokus with very few given digits, generally — 2026-02-09
• Like a 1,000-piece monochromatic jigsaw puzzle — 2025-04-30
• Like diamonds and calculus problems — 2025-04-14
• Word with copy or currency — 2023-10-26
• Forcefully — 2022-12-24
• Like Parmesan and pecorino — 2021-01-10
• Like a Saturday crossword — 2020-12-08
• Tough — 2019-10-30
• Like a rock and many a roll — 2019-07-12
• Like walnut shells — 2019-03-27
• With 60-Down, gotten by great effort — 2016-07-08
• Herculean — 2015-07-19
• Brain-busting — 2015-04-30
• You might give this to someone you don't like — 2012-06-28
• Kind of rock or candy — 2012-05-11
• Fatiguing — 2011-05-05
• Brain-busting — 2010-01-24
• ___ as a diamond — 2009-04-28
• Difficult — 2008-04-21
• Rocklike — 2008-03-17
• Obdurate — 2008-01-23
• Compact — 2007-09-08
• Rocklike — 2007-06-18
• Steellike — 2007-06-04
• Not liquidy — 2006-12-31
• Like some cider — 2005-04-07
• Verifiable, as facts — 2004-04-11
• Knotty — 2003-04-01
• Brain-busting — 2001-10-29
• Arduous — 2001-07-16
• Granitelike — 2001-07-03
• Stony — 2001-05-01
• Brainbusting — 1998-09-14
• Like some candy — 1998-05-08
• Like a Friday crossword — 1997-07-25
• Like Hannah's heart, in song — 1997-01-12
• Herculean — 1996-10-04
• Like #4 pencils — 1995-05-14
• Difficult — 1995-03-29
• Rocky — 1994-10-05
• Difficult — 1994-10-04
• Granitelike — 1994-03-02