Definition
A transformation steering group led by the top leader and composed of several executives with resource and personnel authority; members first personally complete immersion and Kaizen practice, then jointly design and drive the organization's introduction plan. From a publicly published book, not textbook terminology.
In detail
Transformation cannot rely on the top leader alone, nor can it be handed entirely to the transformation office. The Guiding Coalition brings in the few executives who truly hold resources and personnel authority, has them personally participate in Kaizen Events, jointly set objectives and cadence, and speak with one voice externally. The prerequisite is that members have "done it" rather than "heard about it"; executives who attend only a half-day kickoff learn nothing and signal to the organization that transformation is not important.
Example in practice
Before the transformation launch, the general manager invites the four heads of operations, sales, finance, and HR to form a Guiding Coalition, with each person fully participating in at least one Kaizen Event in the first three months; the coalition meets every two weeks to align on "why change and where to change first," and jointly decides the first Model Value Stream and the transformation office staffing.