Deletion from the Ritual section
I have deleted the following:

"This head cut is not supposed to go all the way through the samurai's neck: honor dictated that the cut shall finish just before completely beheading the samurai that has committed the seppuku. Complete decapitation was considered a grave dishonor and disgrace."

Reason: there is nothing to substantiate this at all. The only thing I have come across that suggests that leaving a piece of skin was at once considered "ideal" is from the Hagakure, and even there it was not a matter of disgrace. In fact, in the Hagakure, Yamamoto Tsunetomo advocates cutting all the way through - better to do the job properly than risking botching the job: "In the practice of past times, there were instances when the head flew off. It was said that it was best to cut leaving a little skin remaining so that it doesn't fly off in the direction of the verifying officials. However, at present it is best to cut clean through." Of course, the notion that a 10 lb head should go "flying off" (presumeably from the blood pressure) is absurd. This was likely just an urban legend back in the day in Japan.