To improve at Sudoku, you need more than just solving puzzles. You need a way to measure your progress. The direct answer is to time each attempt and write down the result. By recording how long a standard 9x9 puzzle takes you, then comparing that time over several sessions, you can see exactly where you are getting faster. This post explains how to do that, what tools to use, and how to handle different variants.

Why Timing Matters for Improvement

A standard Sudoku has a 9x9 grid of 81 cells divided into nine 3x3 boxes. Each row, column and box must contain the digits 1 to 9 exactly once. A well-made puzzle has exactly one solution and can be solved by logic alone, without guessing. When you time yourself, you create a baseline. Without a number, you only have a vague sense of whether you are getting better. Timing each attempt and writing down the result is a simple way to see improvement over several sessions.

A stopwatch counts up from zero, which is useful for seeing how long a single puzzle takes. A timer counts down from a set time, which is useful if you want to push yourself to finish within a limit. Both work. The key is consistency: always time the same way, on the same difficulty level, and write down the result immediately.

How to Start Timing Your Solves

Start with an easy puzzle. Use a stopwatch on your phone or a physical stopwatch. Press start when you first look at the grid, press stop when you fill the last cell. Write down the time in a notebook or a simple spreadsheet.

  • Always solve on the same device or with the same method (pen and paper vs. online).
  • Do at least five puzzles at the same difficulty before comparing times.
  • Ignore the first few timed solves; they will be slower because you are adapting to the process.

Tracking Your Progress

After each session, look at your list of times. If the average time from your first five solves is 12 minutes, and your next five average 10 minutes, you are improving. The minimum number of starting clues for a unique solution is 17, proven by computer search in 2012, but most published puzzles have more clues and vary in difficulty. Stick to one source or one difficulty level to make comparisons fair.

Using Difficulty Levels to Challenge Yourself

The puzzle was popularised in Japan under the name Sudoku and spread worldwide in 2005 after newspapers began printing it. Most modern online platforms offer several difficulty levels. If you are using a site like sudoku.by, you have six levels: Easy, Medium, Hard, Expert, Master and Extreme. Start at Easy and time five solves. When your times become consistent, move to Medium. This stepwise approach keeps you in the zone of productive challenge.

Do not jump from Easy to Extreme. The jump in logic required might frustrate you and make timing useless for tracking progress. Instead, move one level at a time, and only when your average time for the current level drops below a threshold you set (for example, under 8 minutes for Easy).

Timing Different Sudoku Variants

Variants change the rules and require different strategies. Timing them separately is essential because a 10-minute solve on a standard Sudoku does not compare to a 10-minute solve on a variant. Here are a few common variants and how to approach them:

  • Killer Sudoku adds cages whose cells must add up to a given sum. You must combine the sum logic with standard placement. Expect your times to be longer at first.
  • Diagonal Sudoku also requires 1 to 9 on both main diagonals. This adds extra constraints that can speed up the solve once you are used to them, but will slow you down initially.
  • Samurai Sudoku overlaps five grids. Each grid follows standard rules, but the overlap means a digit placed in one grid affects another. This takes significantly longer.
  • Jigsaw Sudoku replaces the 3x3 boxes with irregular shapes. The shapes change the visual scanning, so timing a few solves will help you adapt.

Why Track Variants Separately

If you mix times from a standard puzzle and a Jigsaw puzzle, your average time will be meaningless. Keep a separate log for each variant. Over several sessions, you will see which variants you are naturally faster at and which need more practice.

Practical Tips for Consistent Timing

Here are practical steps to make your timing data useful:

  1. Use the same tool every time. If you use a stopwatch on your phone, do not switch to a timer app mid-session.
  2. Record the date and difficulty. A simple log like "March 15, Medium, 9:32" is enough.
  3. Do not reset the stopwatch if you make a mistake. Include the entire time. It reflects your real solving speed.
  4. Take a short break between solves. Five minutes of rest helps maintain focus and gives you time to write down the result.

You can also use a timer that counts down from a set time to create a speed target. For example, set a timer for 10 minutes and try to finish the puzzle before it reaches zero. This adds pressure and can help you learn to work faster, but do not use it until you have a baseline from stopwatch timing.

If you want to practice with many variants and difficulty levels, you can play Sudoku online at sudoku.by, which offers daily challenges, leaderboards, weekly competitions, and over 30 variants including Killer, Diagonal, Samurai, Jigsaw, Thermo, Arrow, Sandwich, Kropki and Mini 4x4. The site also provides technique guides and saved progress, making it easy to time your solves consistently.