Cantered again today, same lead.  He picked it up, cantered quietly, came back quietly.  Very happy.  On his difficult side, the right, we didn't.  Will try next time.  Just like the left lead, which I know now he will do without difficulty, he needs to get used to the idea.  Also, because it is his difficult side, the best thing is to ask but not make a big deal (unless he gets it!).  On line got the best full pass we've ever done.  Accidentally flicked him with the end of the carrot stick string.  A happy accident it seems for he full passed both directions like a professional.  Which brings up the obvious question.  Why, if he understands it so well and is capable of accomplishing it with such ease, has he not done so?  Am I too nice?  I reward the merest try.  Perhaps now is the time to be a bit more insistent, to not reward until he's tried a little harder for a little longer.  I've been happy with one full step.  We tried a new exercise at the end of our 25 minutes? under saddle.  There are two 20L drums in the arena.  I asked him to walk very tight around the drum then gradually spiral out until the circle was large enough to ask for trot.  He found it easy to the left and difficult to the right.  But with a little effort from both of us he held his line, didn't fall in or out of the circle and stopped square!  That was good enough for me.  We quit and I took him out on the road for pick.  I like spending time with him like that.  He grazes and I know he's happy tasting green after this long winter.  He  raised hs head and touched me with his nose  which I interpreted as just a friendly checking in.    Quite companionable.