Notching

On the first notch I tried scribing the contour of the lower log onto the upper log then made a series of vertical cuts down to the line. Once the cuts were made I used the hatchet to knockout the chunks.

That made a nice snug fitting joint but it was very time consuming and hard to carve the contour out with only the hatchet and no chisel so I'm going to stick to the simpler "V" saddle notches from here out. Just cut two angles to the appropriate deepth on the edges and knock out the middle using the hatchet/axe whack method.

First seven  notches cut and joined!