With a western saw which cuts on the push stroke, if you push
straight down you're cutting acrossed end grain - slow, If you
angle the handle back towards you while you're above the wood,
the teeth will be cutting "downhill" angled acrossed the grain
-faster. But with a japanese saw, the teeth cut on the pull
stroke so if you're above the board and have the blade angled
handle high - you're cutting "uphill" into the end grain first
slow and proned to tearing the grain rather than severing it.

Nora Hall, a great carver, uses the Straw Broom Analogy.
If you try and carve INTO the straw bristles from the
sweeping end the bristles the straws bend and break
rather than being cut. Cut towards the sweeping end
and there's no problem.

Or - think of using a chainsaw to cut a log - the bottom
teeth coming back at you are similar to the the teeth
of a japanese saw cutting on the pull stroke. Go here
and replace the chainsaw with your japanese pull saw.
The second set of illustrations my help you understand
why you're getting tear out as the saw exits the wood.

http://web.hypersurf.com/~charlie2/T...insawing2.html

When ripping with a japanese pull saw - from above
the tip of the saw blade is closer to you than the
handle. When sawing from below, the handle is
closer to your than the tip of the saw blade.

charlie b