  This paper is an ideal continuation of the previous one - How to enhance
effectiveness of Direct Attack Judo throws -in it there are analyzed the two
following parts of Judo tactics in high level competitions: combination, and
action-reaction. The paper start with a review of the Japanese approach to
Initiative ( Sen) and follows by the biomechanical view of the same subject.
High level competitions are the main argument not only of coaches match
analysis , but also of a lot of scientific researches. However the connection
between these two field that analyze the same subject is very hard . A lot of
information are not easily transfer to coaching area. In this paper the effort
to give coaching useful information is the primary aspect also at detriment of
some formal mechanical information. After a new Operative Classification of
throwing techniques , the biomechanical analysis of combination and
action-reaction tricks flows in easy way singling out some interesting finding,
useful for coaches. With this effort the biomechanical analysis of judo
Interaction in high level competition could be considered completed
