Complex sentence: In those days, aiki budo was still a very hard martial art and training at the Kobukan was intense, and it was this kind of training that Shioda loved and strove to preserve when he later founded the Yoshinkan.
Split into simpler sentences: In those days, aiki budo was still a very hard martial art and training at the Kobukan was intense. It was this kind of training that Shioda loved and strove to preserve when he later founded the Yoshinkan.