This is definitely the most famous kanji tattoo in Japan. Just google the word "精哲力"and see how many hits are there. As of the end of June 2012, there are 7,330 hits for the exact word. There is no such word as "精哲力" except for this particular tattoo design, and all the hits refer to his tattoo!
It reads "sei" (精) "tetsu" (哲) "ryoku" (力) from top to bottom, meaning "spirit" "philosophy" and "power."
"sei" (精) could also mean sperm (精子).
Spirit and power parts are understandable, but what is philosophy part about?
