The Training Roadmap

Master the algorithm step-by-step through focused mini-games

Foundations

Learn the core memorization building blocks.

Find the doomsday for a given month in a non-leap year

Find the correct number for a given weekday

Find the correct anchor day for a given century

Is the given year a leap year?

Master the mental math that turns a year into its doomsday. There are two roads through this step — pick the one that suits your head.

How many whole 12s fit into the given number

Find the remainder after dividing by 12

How many whole 4s fit into the given number

Find the modulo 7 of the modulo 12 plus its divisor of 4

Find the anchor doomsday for any month or year.

Find the doomsday for a given month and year

Find the correct doomsday for the given year

Put it all together and solve full dates instantly.

You’re told the month’s doomsday and its weekday — count to the date

Find the day of the week for the given date

Find the day of the week for the given date

Find the weekday for full dates from a range you choose — pick the centuries and years you want to drill