Gi,
Yoshinkan aikido was started by Gozo Shioda in the 1950s. Shioda had trained directly under aikido's founder, Ueshiba Morihei, for 8 or 9 years before WW2. During that time Ueshiba was still teaching in a style that was much closer to his Daito-ryu roots than what his aikido evolved into after the war. So, Shioda learned a system that is closer to Daito-ryu than to much modern aikido in many respects.
That is a very nice video of Yoshinkan aikido. You can see a number of unaltered Daito-ryu techniques in it. I also see numerous technical similarities to our style of hapkido.
Generally, Yoshinkan and a couple of other styles, like Tomiki aikido and Nihon goshin aikido, are considered "harder" styles than the modern version of Ueshiba's style.
