Sparring
 The teacher (on the left, in blue) has better extension here - and so can strike further. Another member is in back where the judge would stand. But he also warns those sparring when they move to far toward the side. =======>  
Neither person is close enough to touch the other; proper distancing is important. The teacher blocks a wrist strike (kote) without moving his shinai much leaving the student's shinai is in an awkward position.