EventStorming starts with a brainstorm of the domain events related to the business domain being explored. A domain event is something interesting that has happened in the business. It’s important to formulate domain events in the past tense (see Figure 12-2)—they are describing things that have already happened.

1 Of course, that’s not a hard rule. Leave a few chairs if some of the participants find it hard to be on their feet for so long.

Figure 12-2. Unstructured exploration

During this step, all participants are grabbing a bunch of orange sticky notes, writing down whatever domain events come to mind, and sticking them to the modeling surface.

At this early stage, there is no need to worry about ordering events, or even about redundancy. This step is all about brainstorming the possible things that can happen in the business domain.

The group should continue generating domain events until the rate of adding new ones slows significantly.