thanks for such quick thoughtfulness- yes, it's through a 2X6 mortise, 6" deep.
the check goes in radially straight towards the heart, which is sound and centered in the timber.
i wasn't intending to house the joint. there's not quite enough room- the beam is 8" wide and the posts 7", the thought being, with a little roof of flashing on the beam, that the rain doesn't drip down the works.
