I was practicing with my son this past weekend on noodles and some bottles. Using an ATrim 1516 he made a nice combination cut on one noodle stood vertically on our stand that nicely captures how noodles behave/react when cutting them with a sword, and therefore the limitations of that kind of material as a medium for cutting practice. You can see in the photo the noodle fragment with two cuts off the same mark, the one on the top is a slice upwards (underhow) and to the left and the second is a slice downwards (oberhow) and to the left. note the upward cut is slightly concave, the oberhow slightly convex. also note the smoothness of the underhow cut, the roughness of the oberhow cut.

the point is that the material reacts differently depending on whether it is being put into tension or compression as the blade enters the material. cutting upward puts the material in this case in tension along the long axis of the noodle. the opposite is true in oberhow, the noodle compresses. because of the type of material (porous, very compressible), the material shears very differently in compression than tension. i find this is true with tatami as well, but is accentuated with such a compressible material as a noodle.

not rocket science here, obvious, and probably a repeat of previous postings but i thought i would share given the recent discussion on "cutting standards" for swords. tr

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I find using half a foam noodle creates much less bending. Otherwise they really want to lay over when struck.

I can get straight cuts with no curving that way.

yes that is a good recommendation, we always cut them in half (or thirds) to start. i have an adjustable pole (an aluminum window washing pole cemented into the ground that you can loosen by rotating and adjust up/down) that we use with noodles so we can vary the height of the target...... i don't remember how long the total piece was when this particular fragment was sliced off, probably a third of a noodle or less. i just thought it was nicely illustrative of the compression/tension effect. he is truly learning! he hit the mark nicely, i have trouble being that accurate on the same mark with two consecutive fast cuts........

I use PVC pipe instead of anything harder. At one point or other, all of my swords have hit the pipe on accident. The pipe gives before the sword will. :) I use short lengths with couplers/joints to add segments. That way I can control the height and easily replace pieces if they get damaged.

hadn't thought of pvc, thats a good thought. the end of my pole has a threaded plastic fitting for where you would screw in a mop or broom head, to give us the additional safety margin i have a two foot long piece of bamboo on the end of the aluminum, then the noodle is socketed over that. and yes, the bamboo has had to be replaced several times :) tr

Something to keep in mind is that on one side of the blade some material will be compressing and on the other some will be tensioning in the midst of other material being bent at the same time!
Shear, I believe plays a fair role in this as well... the forces involved in cutting is probably far more complex than I can appreciate.