A compensatory strategy for improving working memory (WM) constraints that are experienced when playing a simplified version of Mastermind was investigated. Formal analysis suggested two feasible play strategies: focusing and tactical. Although the focusing strategy was expected to cause lower WM load and was predicted to compensate for WM constraints, it was considered to be theoretically less efficient than the tactical strategy, which was considered to be theoretically more efficient, but was expected to cause higher WM load. The performance of 45 junior college student participants who were induced to use the two strategies was assessed in Experiment 1. The WM level of all participants as measured by the Reading Span Test indicated a low span. Results indicated that the focusing strategy was more effective than the tactical strategy. In Experiment 2, 10 college student participants increased their spontaneous use of the focusing strategy. These results suggest that the focusing strategy compensates for WM constraints of participants with a low span. The effects of the compensatory strategy for WM constraints in problem solving are discussed