Human Resources should also be involved at the very beginning of the Kaizen process, for several reasons:

Some pre-training is helpful, in order to prepare the workforce for the changes that are coming. A “Change Management” class would be a good idea. “Participative Management” is another topic that would be helpful in preparing the Kaizen teams.
Some screening of Kaizen participants may be necessary. It is very important to have people on the Kaizen teams who want to be there, who are open to change, and who work well with others.
Finally, the HR representatives need to understand and support the Kaizen process. In that way they will be ready to deal with issues and questions when they arise during the actual Kaizen process.