Time required:

60 min

Number of participants:

A group of people working on the same challenge


The 9 A3 sheets printed out, cut out and hanged on a wall to create a full poster
Sticky notes / postits
sticky dots


Yasuo Matsumura


Want to hear more about Make brainstorming easy and fun: Brainstorm Sudoku?

Want to hear more about Make brainstorming easy and fun: Brainstorm Sudoku?

What is an idea?

An idea is merely a thought or notion of an element or loose concept pointing to a possible solution or plan for action. An idea in this context does not need to be realistic or fully thought through. Bad ideas can inspire good ideas, so do not hold those back! :)

Understanding the model

The tool addresses two of the biggest barriers to generating many ideas and good ideas. The first is the notion that good ideas come just because you are in a group. Recent research suggests that the best ideas arise when you are alone. However, it also shows that good ideas improve when you collaborate on them. Therefore, it can be beneficial to take a break, maybe even a few days, after defining your innovation question (HMW) and before starting to generate ideas. This provides time and opportunity for good ideas to arise in each individual. To accommodate this, the Brainstorm Sudoku tool is divided into two rounds. The first round focuses on capturing the initial and immediate ideas that each individual comes up with. The second round is about further developing the ideas from the first round.

The second barrier the tool addresses is that we often don’t have a quantitative boundary for our brainstorming. This means we quickly run out of steam, as we can hardly judge whether 14 or 38 ideas are the right number to find the right idea among them. As a result, we rarely exploit our creative potential because we don’t know when we are done with our brainstorming. You can complete the Brainstorm Sudoku. It can be filled out completely, making it much easier to also write down really bad and silly ideas, as participants can focus on finishing rather than the quality of each idea. Bad and silly ideas are important, as they often inspire truly good, brilliant, and innovative ideas.

The tool comes in the original 8×8 model or a smaller and quicker edition. This smaller edition, can be downloaded here.

How to use the tool

  1. Place your HMW question in the center of the poster.
  2. In silence, come up with 8 (4 if you are using the smaller version) ideas that could be answers to the HMW question. Place them in the inner boxes.
  3. When those 8 (or 4) ideas are on the board, go through them quickly one by one (one sentence to describe each idea).
  4. Again in silence, come up with up to 8 related ideas for each of the original 8 ideas. This gives you many more focal points to start your ideation from. If you cannot come up with more ideas related to one, you can always change focus to one of the others. (If you are using the smaller version, come up with 8 ideas in total related to the first 4 ideas.)
  5. Try to work fast and fill up the entire board (56 ideas in total). Brainstorming is not about coming up with good ideas but about coming up with a lot of ideas to choose from. So try to identify the unusual and maybe crazy ideas as well.

Brainstorming rules:

  • It’s all about being open to exploring new opportunities (divergent mode).
  • Do not say NO or BUT. Instead, say YES and AND.
  • At this point, quantity is more important than quality.
  • Stupid ideas might inspire great ideas.

Deciding on which ideas to pick out:

Dot Voting – Go for the option with most energy

Purpose and functions of the tool

Dot voting is for taking quick and energy-based decisions in groups.
The principle of dot voting is simple. From a vast set of ideas you give each group member a number of sticky dots to place as their vote.

The purpose and aim are to narrow down the number of ideas to focus on the ideas that the team believes in the most. That makes it easier to make the decision of which one idea to move on with


  1. Give each group member 3 dots
  2. In silence spend a few minutes looking at the board and decide by yourselves where to place your dots
  3. When everybody knows where to place the dots, count down from 3 and place all the dots at once. (To avoid affecting each others decisions)
  4. Take away the ideas without any votes, and discuss which one idea to move on with.
  5. Once you have chosen one or a few ideas, it can be useful to make a Pre-concept for each.


Examples in use:

Other tools and methods:

  • Speeddating your user while making personas

    When it's not possible for you to talk directly with your user, you might invite them on an imaginative date?

    Speeddating your user while making personas

  • Thing of the Future – A Speculative Warm-Up

    Go to the future to challenge your assumptions, biases and suspend your inner critical voice, by using this tool originally designed by Stuart Candy

    Thing of the Future – A Speculative Warm-Up

  • 5 Step Storyboarding
    – Use storytelling as prototype

    Test, test, test.. You can never test your ideas ioo early or too often. The 5 Step Storyboard is a quick way to communicate your idea and get feedback.

    5 Step Storyboarding
    – Use storytelling as prototype

  • Give shape to your idea – The Pre Concept

    Create Pre-Concepts for your early ideas to better assess what will work and what needs further development.

    Give shape to your idea – The Pre Concept