In our class tonight... well every night, we warm up with ukemi and taihenjutsu drills. These are so fundamental to Bujinkan training that I do them every class. What is also fundamental is to try them ryote, katate and mute. That is: two handed, one handed, and no handed. This way you are prepared for nearly any situation requiring evasion or hitting the ground. Two handed gives the most control. You can use the ground as your ally and "steer" your interaction with it or be steered by it. You might discover something there to aid in your counter or as metsubushi. One handed can be necessary if one hand is otherwise occupied. Maybe you are being thrown by a joint lock on one arm. Perhaps one arm is injured. Perhaps one hand is drawing a weapon as you evade an attacker. In any case, you should know how to do this with the lead or rear hand. No handed is the most acrobatic. This takes the most control with the legs....
Train smart. Live better.