DH

The technique is ippon-dori. The first standing waza of Ikkajo. Ueshiba picked it for his ikkyo.
The idea is to stop the opponents sword strike and cause kuzushi. Yeah, good luck with that! The punch is supposed to be a knife strike to the upper ribs/armpit area. Then you switch to a wrist grab and end with a knee and a motion like a spear thrust (with his arm as the spear) to plant him. Overly complicated and marginal at best against a weapon- never mind bare-handed. There are other Koryu with similar moves done far more simply and directly with a blade controlling the blade-Takenouchi is one, Sho-sho ryu another. Overall the percentage of probability done bare-handed is ridiculous.
That particular line of DR shares nothing in common with its jujutsu waza to the other schools. As it is, many of the forms are done stiffly, and are many times inconsistant with other forms of Koryu jujutsu. Common discussions among the more learned crowd are that they appear either fabricated by someone unfamiliar with armed fighting, and or armored fighting, or an attempt at using aiki by someone lacking those particular skills. It's as if they are stuck in the middle of trying to be something they are not. DR is frequently criticized for many of the same reasons as Aikido in the Koryu community. And for some very good reasons.

DR and the sword
Like aikido were one to assume DR people know anything about the sword is hilariously awry. Unless they trained in a koryu-they don't have a clue. Case in point: during the 50 yr. celebration with all schools gathered, Kondo was chastised by Mochizuki for daring to even appear with a sword in his hand (to demonstrsate shiho-nage). Mochizuki boomed that "You Daito ryu people don't know anything about the sword!" He told his men to go get their swords out of their cars, and then did a short demonstration.
Kondo was humble enough to share that story on his first trip to the U.S.

Recently a long time student left DR for the above reasons. As a Koryu of cohesive school, the art is a mess, and no one had the real koryu weapons skills they so often talk about to even fashion any sort of meaningful defense against them. Grabbing the wrists of someone cutting you with a sword and reversing their shoulder while opening them for a thrust is just plain ridiculous. Unless the swordsman was a...well...inexperienced hobbyist-you'd get killed.
I could enter a list of prominent Koryu teachers and their private reviews of DR, but if they wanted to make it public, they either already have or have no interest in doing so.

Consistency in Mokuroku and transmission
Were one to try and define Daito ryu as a Koryu, or a cohesive, school with a supposed linear transmission, with a cogent consistant catalogue, they would fail. It is not as if the schools are doing similar but somewhat different syllabary. They are completely different. In essence they are different schools. IME all based on the few who attained real internal skills recording and teaching the various ways the Uke jump or react from the power. Even today teachers are creating/discovering/changing as they grow in power and sensitivity..
With the the remaining schools a technically cohesive mess one to another- the only choice is to find the better teachers who have aiki (internal power) instead of just jujutsu. And of those, find ones who can and will teach. This may be allot more difficult than you think.

Functional origins of techniques
The power of DR is in its body method, not in the pretzel logic. The functional "origins" are unknown, and explanations for "them" (since "they" are all over the place) are as varied as the five DR schools waza are. It is probably wiser to consider the explanations for these incredibly inconsistent techniques as unsupported legend, rather than unchanged and cohesive, waza transmitted down through time.