Cobalt in Red Herring
Cobalt has appeared on 9 boards: 9 times inside a themed group and 0 times as a red herring. That is a 0% decoy rate.
Is Cobalt a Red Herring?
Every appearance of Cobalt across the 3,529-board archive, and whether it belonged to a group that day or to the herrings.
Groups it has belonged to
Cobalt on 9 Boards
Newest first. Red panels are the boards where it was a decoy — those are the ones worth remembering.
What the Puzzle Said About Cobalt
December 5, 2017
Cobalt, a silver-gray metal, isn't found as a free element in nature.
July 18, 2020
Cobalt, a silver-gray metal, isn't found as a free element in nature.
March 1, 2023
Cobalt, a silver-gray metal, isn't found as a free element in nature.
September 12, 2025
The lustrous, silvery metal cobalt is used in lithium ion batteries.
April 30, 2026
Cobalt, a silver-gray metal, isn't found as a free element in nature.
Using a Word's History Without Being Fooled By It
A high decoy rate is a warning, not a rule
Cobalt has been a red herring on 0% of its appearances. That makes it worth leaving until last, not worth discarding — the board decides, and the three-group structure is what settles it.
Themes repeat, words move between them
This word has sat in 4 different themes. A returning theme brings different members with it, which is why the category pages show every word a theme has ever used rather than a fixed four.
Count to sixteen first
Three groups of four plus four herrings. Four words are meant to be left over, and expecting that is what stops you forcing a fourth group that was never there.
How to Solve a Red Herring Board
The order that clears a board fastest.
Count to sixteen first
Three groups of four plus four red herrings. Four words are meant to be left over — see any board in the archive.
Lock the tightest theme
Solve the most specific group first; each correct group removes four candidates from everything else.
Distrust the near-miss
A word that almost fits two groups is usually a decoy — which is exactly what a page like this one records.
Verified Answers, Not Guesses
How we verify every board Cobalt has appeared on, and whether it was an answer or a decoy each time
Word histories are built from the 3,529 dated boards in our archive rather than from any published list — the source has no word pages. Each appearance links to the board it came from so it can be checked. The routine is in our methodology and the standards in our editorial policy.
Reviewed by Priya Raghunathan, Word Games Editor at Puzzle Solved. The full checking routine is in the methodology, and the standards every page is held to are in the editorial policy.
Last checked — Aug 25, 2026