<i>In the 1970's, the Japanese courts forced So Doshin to the change the name of his school to Nippon Shorinji Kempo.</i>
This is untrue. I suspect your erroneous source was Donn Draeger, but as Draeger (ironically) died in the same year as So Doshin, I cannot quiz him to verify.
What actually happened was that a former Shorinji Kempo (SK) 7th dan sued SK HQ (Hombu) for the right to use the name SK even though he was no longer affiliated with So Doshin or the HQ in Tadotsu. The judge ruled that FOR THE PURPOSE OF THE COURT CASE ONLY, So Doshin's art was to be called "Nippon Shorinji Kempo" in court to distinguish it from any style practiced in China (the terms "Shorinji Kempo" and "Saolin-ssu Chuan fa" being pronounced the same in Japanese). So Doshin (Kaiso)'s art is still called "Shorinj Kempo" in Japan, with absolutely no use of the "Nippon" (although there is a completely different art called "Nippon Kempo" that has no relation to Shorinji Kempo).
You might want to update the information in this thread.
I only do Shorinji Kempo for kicks.