The Times Killer Sudoku

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The Times daily killer sudokus, where cages add up to given sums.

on thetimes.com

Times Killer Sudoku No 5684 Deadly part solved on The Times web player in 2017, dotted cages with their totals and a 1 to 9 keypad, from a solver's YouTube video

Killer Sudoku from The Times adds sums to sudoku: the grid is split into dotted cages, each with a total, and no digit repeats in a cage. New numbered puzzles appear every day at more than one level.

About The Times Killer Sudoku

Killer sudoku began in Japan, and its first appearance outside Japan was in The Times in 2005. The paper has published it ever since, and today it sits next to the classic sudoku in The Times puzzles section online and in the Times Puzzles app.

The grid is a normal nine by nine sudoku with few or no starting digits. Instead, the squares are grouped into cages drawn with dotted lines, and each cage shows the total of its digits. Every row, column and three by three box still holds the digits 1 to 9 once, and no digit repeats inside a cage. The Times publishes new numbered killer sudokus every day at more than one level, with names running from gentle and moderate through tricky to deadly, and the app also carries extra killer puzzles on some days.

It needs a Times digital subscription on the website, or a Times or Times Puzzles subscription in the app, which keeps a two-week archive. It suits sudoku solvers who want some arithmetic in the logic: much of the work is in knowing which digits can make a cage's total, and in adding up whole rows and boxes, which always total 45.

How to play The Times Killer Sudoku

Sign in with a Times subscription and open the sudoku page on thetimes.com, or the Times Puzzles app.
Pick one of the day's numbered killer sudokus by its level.
Read each cage's total: the digits inside the dotted outline must add up to it, with no digit used twice in the cage.
Fill the grid so every row, column and three by three box holds the digits 1 to 9 once.
Use pencil marks for the digits a cage can still hold, and narrow them down until the grid is complete.

Screenshots

The Killer Sudoku list in the Times Puzzles app: Killer Sudoku No 8340 Tricky, No 8341 Deadly and Extra Killer Sudoku No 451 Gentle, each with Start puzzle

Tips

Learn the fixed combinations: a two-square cage of 3 must be 1 and 2, of 17 must be 8 and 9; a three-square cage of 6 is always 1, 2 and 3.
Every row, column and box adds up to 45. Add the cages inside one, and the difference tells you the digit in a square that sticks out.
Start with small cages that have one possible set of digits, then with cages wholly inside one box.
Write the possible combinations for a cage beside it before placing digits; they rule out digits in the rest of its row or box.
On deadly levels, try the 45 rule across two or three rows or boxes at once.

Questions

What is killer sudoku?

A sudoku where the grid is divided into cages with totals. As well as filling every row, column and box with 1 to 9, the digits in each cage must add up to its total without repeating.

How many killer sudokus does The Times publish each day?

More than one, each numbered and graded, such as moderate and deadly. The Times Puzzles app adds an extra killer puzzle on some days.

Is The Times killer sudoku free?

No. It needs a Times digital subscription, or a Times Puzzles subscription in the app.

Did The Times invent killer sudoku?

No. It began in Japan, but The Times was the first paper outside Japan to publish it, in 2005.

When do new puzzles appear?

Once a day. The Times does not state the time.