Roger Martin's theory of "where to play and how to win" is a strategic approach that helps organisations determine the most promising opportunities for growth and identify the best ways to succeed in those markets.

The "where to play" component of the theory is about selecting the most attractive markets or segments for the organisation to compete in. 

This involves analyzing the market, the competition, and the organisation's strengths and weaknesses, to identify areas where it can create unique value for customers and achieve a sustainable competitive advantage. 

Martin suggests that organisations should focus on markets that have unmet customer needs or are underserved by competitors.

The "how to win" component of the theory is about developing a winning strategy to compete effectively in the chosen market. 

This involves creating a value proposition that aligns with customer needs and the organisation's strengths, and designing a business model that delivers that value at a profit. 

Martin suggests that organisations should focus on creating a distinctive value proposition that is difficult for competitors to copy and building capabilities that enable them to execute that strategy effectively.

Martin’s steps are as follows:

To begin the strategy-making process, you need to frame a choice. Convert your issue into at least two mutually exclusive options that might resolve it. Once you have framed the problem as a choice, your analysis and emotions will focus on what you have to do next, not on describing or analysing the challenge.

Broaden your list of options to ensure an inclusive range of possibilities. A possibility is essentially a happy story that describes how a firm might succeed. The team must produce more than one possibility. Otherwise, it never really started the strategy-making process because it didn't see itself as facing a choice.

For each possibility, specify conditions: what must be true for it to be strategically sound. Then ask, “If all these conditions were true, would you advocate for and support this choice?”

To strengthen the possibilities further, it’s time to identify barriers - which conditions are least likely to hold true. Work to eliminate or mitigate these barriers.

Then we can test against the barrier conditions - and start with the the condition the group feels is least likely to hold up. Devise a test you deem valid and sufficient to generate commitment for each key barrier condition.

Finally, make a choice - review your key conditions in light of your test results in order to reach a decision.