The goal
You'll be shown a random date. Your job is to figure out which day of the week it fell on — Monday, Tuesday, and so on — and tap the correct button before time runs out (or before you get one wrong).
Play styles
🔥 Streak — one strike and you're out. Answer correctly as many times in a row as you can. Your streak is saved automatically, so you can resume a run later.
⏱ Speedrun — you have 2 minutes on the clock. Answer as many dates as you can before time runs out. Wrong answers cost you a 10-second penalty.
Year range
Set the range of years you want dates drawn from. A narrow range (e.g. 1990–2010) is easier to start with; widening it makes the mental arithmetic harder.
The Doomsday method
The fastest way to solve any date is the Doomsday algorithm. The idea has two parts:
Step 1
Find the Doomsday for the year — a specific day of the week that certain easy-to-remember dates always share.
Step 2
Count forward or backward from the nearest of those anchor dates to reach your target date.
For example, if Doomsday for a year is Wednesday, then the 4th of April, the 6th of June, the 8th of August, the 4th of July, and several other memorable dates are all Wednesdays that year. From there, counting a few days in either direction gives you any date.
The 💡 Hint button
During a game, tap 💡 Hint to see the full working — the Doomsday for the year, a step-by-step breakdown of how it was calculated, and all the anchor dates with the nearest one to your puzzle date highlighted.
Tips for beginners
Start with a narrow year range and use the hint every round. The goal is to internalise the pattern — with practice you won't need it at all.