I practice what I would call a soft style. Seidokan was founded by Rod Kobayashi after he left the Ki Society. The best way I can think of to explain it is by re-telling and paraphrasing a story told to me by Eli Landau, a Seidokan instructor in Isreal.
My apologies to Landau Sensei for the mistakes I'm about to make in the re-telling.
I was nearly ready to quit aikido. I was frustrated. All my teachers kept telling me that aikido techniques didn't have to hurt, but every time they did one to me it hurt. Not one of them could do the technique without the pain like they claimed it could be done. Then I met Kobayashi sensei. I grabbed his wrist and he touched me here and I fell down. I attacked again and he touched me over here and I fell down. I got up and thought AHA, aikido doesn't have to hurt! That was when I started following his teachings.
Again, my apologies for the butchering of the story but that's my memory of it.