Field notes
Domain knowledge is usually scattered across several people at once: business folks, developers, operations, support. No single person holds the whole picture. Traditional methods (requirements documents, UML, storyboards) usually start at the data model or the UI sketch, and therefore risk missing the moments where something meaningful happens in the business. EventStorming turns that around and starts at the other end: what is it that should occur, seen from the business's perspective? Then the human decisions, the boundaries, the aggregates and so on surface "of their own accord".
EventStorming is a collaborative workshop technique developed by Alberto Brandolini. The idea is to quickly visualise a domain behaviour by collectively naming domain events in chronological order on a long wall.
Running the workshop together in the same room is by far the best option, but sometimes it is worthwhile to bring the result into a digital tool for further refinement afterwards. And sometimes digital collaboration simply has to do, when the alternative is not possible.
Naming the events is one of several places where the shared vocabulary gets worked out. An event is phrased in the past tense, in the words the business actually uses, so a wall of them is a good start on the Ubiquitous Language. Heard out loud, in the room, from everyone who is there.
A start, though, and not the language itself. And note whose language it becomes: a Ubiquitous Language belongs to the team inside a Bounded Context, not to the business side and not to the developers either. What makes it work is that there is no handover between the roles. The developers are in the conversation, helping both the language and the understanding of the business grow. The domain experts are in the design work, where that same language has to hold up. Both, all the way. That is the trick, and it is why the wall is worth standing at together.
It is also living: it keeps evolving as the understanding does, and a name that was right on the wall may be wrong three months later. It is never set once and for all, and a rename is usually progress rather than needless churn.
When two people in the room name the same moment differently, you have found either a synonym to resolve or a boundary to draw.
Alberto also talks about Value-Driven EventStorming and UX-Driven EventStorming. We have chosen to group these under Process modeling, with a clarifying note so it is clear to the reader what is meant. :)