Master the Double Diamond: A Practical Guide to Solving the Right Design Problems

According to Kengo Kuma’s insight in "Design of Design," design is fundamentally about discovering a problem many people face and attempting to solve it. The Double Diamond design model, proposed by the British Design Association, structures this process into two diamonds: first to find the right problem, then to find the right solution.

Model Overview

The Double Diamond splits design into four stages: discover problems, define problems, develop solutions, and deliver solutions. It is especially useful during product development’s requirement definition and interaction design phases.

Stage 1 – Discover Problems

Deep research into the current situation, including user characteristics, product status, usage patterns, and attitudes.

Stage 2 – Define Problems

Identify the key issues that users care about most, balancing them against team resources to focus on core problems.

Stage 3 – Develop Solutions

Generate a wide range of potential solutions without worrying about technical feasibility; later stages will refine them.

Stage 4 – Deliver Solutions

Analyze, validate, and select the most suitable solution(s) from the pool of ideas.

Application Case: Online Image Viewer

The product "Look Picture Master" aims to increase user volume (WAU). Using the Double Diamond, the team first defined the problem (low new users and retention) and then explored solutions.

Key findings from research:

Limited file format support.

Low conversion rate on the core usage path.

Inconsistent visual rendering.

Proposed improvements:

Add more file formats (e.g., CAD).

Boost conversion on the homepage‑to‑upload funnel.

Enhance rendering precision.

During ideation, eight concepts were generated, such as showcasing multiple use cases on the homepage, highlighting user testimonials, emphasizing the upload button, and adding visual model links. Concepts with low impact (e.g., extra user‑type info, redundant visual links) were discarded.

Value of the Double Diamond

1. Breaks down thinking into logical steps, making the process transparent.

2. Re‑emphasizes asking "What is the correct problem?" to avoid premature solution focus.

3. Makes the design thinking process visible, improving team alignment and efficiency.

In summary, the Double Diamond provides a repeatable framework for uncovering the right problems and delivering effective solutions, applicable not only to product strategy but also to everyday problem‑solving.