Mercury (Mind Loft)
A daily sudoku with thermometers: digits rise from each bulb to its tip.
Every day: One 9x9 thermo sudoku a day, the same for every player, with thermometers along which digits must rise. Weekdays print fewer digits as the week goes on, and the Sunday Edition prints only eight. Daily leaderboard on the clock. New puzzle: Midnight US Eastern Time.
Mercury is a free daily thermo sudoku from Mind Loft. The 9x9 grid has the usual sudoku rules plus grey thermometers drawn across it, and the digits along each one must get bigger from the round bulb to the end. One board a day, with a leaderboard decided on time.
About Mercury (Mind Loft)
Mercury is the thermo sudoku on Mind Loft, a free site of daily browser games. The grid is an ordinary 9x9 sudoku: each row, column and 3x3 box holds the digits 1 to 9 once. On top of that, grey thermometers snake across the cells, each with a round bulb at one end. Along every thermometer the digits must strictly increase from the bulb outward.
There are no sums to work out. The thermometers only set an order, which makes long ones very strong: a thermometer of six cells leaves little room for the digits that can sit in it. Together with a few printed digits, they fix a single solution that can be reached by logic alone, without guessing.
The game does not mark wrong entries, so catching your own mistakes is part of the solve. A clean solve scores 10, and the day's leaderboard is ordered by time. The board has the usual helpers: notes, auto-move, undo, erase and a hint button, plus a count of how many of each digit you still have to place.
A new board goes up at midnight US Eastern Time. Through the week fewer digits are printed, and the Sunday Edition gives just eight with nine thermometers. Mind Loft has a family of sudoku dailies beside it, including Suds (classic), Cages (killer) and Polka (kropki).
How to play Mercury (Mind Loft)
- Open mindloftdaily.com/mercury and press Start to show the day's grid.
- Fill every row, column and 3x3 box with the digits 1 to 9 once each.
- Along each thermometer, make the digits increase from the round bulb to the far end.
- Tap a square and then a number, or pick a number and tap squares; use notes for candidates.
- Finish the grid without errors for a score of 10; your time sets your place on the leaderboard.
Tips
- A thermometer of length n means its bulb is at most 10 minus n and its tip at least n; write those limits as notes first.
- Where two thermometers share a box, compare their lengths to place the low and high digits.
- Wrong entries are not flagged, so check each row and box before you finish.
- The digit counter under the grid shows how many of each number are left to place.
Questions
What is a thermo sudoku?
A sudoku with thermometer shapes drawn on the grid. Digits along each thermometer must increase from the bulb end, on top of the normal sudoku rules.
Does Mercury tell me when I make a mistake?
No. Wrong entries are not flagged, so you need to check your own work. A clean solve scores 10.
Is Mercury free?
Yes. Mercury runs in the browser on mindloftdaily.com at no cost. There is no app and no account to make; entering a display name only puts your result on the daily leaderboard.
When does a new Mercury come out?
Every day at midnight US Eastern Time, with the same board for every player. Sundays bring the Sunday Edition, with only eight printed digits and nine thermometers.
Can I play old Mercury boards?
Yes. Mind Loft keeps past days in its puzzle archive, together with each day's standings.
Games like Mercury (Mind Loft)
Daily Killer Sudoku
A daily variant sudoku where cages give sums in place of printed digits
Daily Jigsaw Sudoku
Another daily sudoku variant, with irregular boxes
Cracked Sudoku
A daily sudoku with unusual shapes and coloured runs to reason with
Good Sudoku
Daily sudoku that gets harder through the week, with a global leaderboard
Daily Thermometers
Uses thermometers too, filled from the bulb in a different logic puzzle
Daily Sudoku (SudokuWiki)
A daily sudoku at several grades for solvers who want more grids
Polka (Mind Loft)
A sudoku with no printed digits: only white and black dots between squares.
Quilt (Mind Loft)
A daily sudoku whose boxes are nine crooked coloured regions.