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The mscroggs.co.uk Advent Calendar is back for its eleventh year, making it the Advent calendar's tenth anniversary! Behind each door, there will be a puzzle with a three digit solution. The solution to each day's puzzle forms part of a logic puzzle:

It's nearly Christmas and something terrible has happened: after years of gradual wear and tear, Santa's magic sleigh has fallen apart. You need to help Santa build a new sleigh so that he can deliver presents before Christmas is ruined for everyone.

The magic sleigh was built from parts bought from magic factories all over the world, and only the exact combination of parts will be magic enough to let Santa deliver all the world's presents on Christmas Eve—but it's been a long time since a magic sleigh was last built and no-one can remember exactly which combination of parts is needed. Behind the first 24 doors on the Advent calendar, there are puzzles with three-digit answers. Each of these answers forms part of piece of information about the sleigh that Santa and his elves can remember: you need to use this information to work out which runners, chassis, present holder, seat for Santa, and front of the sleigh with reins you need to order from the nine suppliers (numbered from 1 to 9) that Santa can order parts from.

You can use this page to try ordering parts for a sleigh, but you can only try ordering three times per day (or Santa's suppliers will get very angry about cancelled orders).

Ten randomly selected people who solve all the puzzles, build a magic sleigh, and fill in the entry form behind the door on the 25th will win prizes!

The prizes will include an mscroggs.co.uk Advent 2025 T-shirt. If you'd like one of the T-shirts from a previous Advent, they are available to order at merch.mscroggs.co.uk.

The winners will be randomly chosen from all those who submit the entry form before the end of 2025. Each day's puzzle (and the entry form on Christmas Day) will be available from 5:00am GMT. But as the winners will be selected randomly, there's no need to get up at 5am on Christmas Day to enter!

As you solve the puzzles, your answers will be stored. To share your stored answers between multiple devices, enter your email address below the calendar and you will be emailed a magic link to visit on your other devices.

To win a prize, you must submit your entry before the end of 2025. Only one entry will be accepted per person. If you have any questions, ask them in the comments below, on Bluesky, or on Mastodon. If you'd like to chat with other solvers, we'll be discussing the Advent Calendar in the #scroggs-advent-calendar channel in the Finite Group Discord: you can join the Discord by following the link in this post on Patreon (you'll need to become a free member on Patreon to unlock the post).

So once December is here, get solving! Good luck and have a very merry Christmas!