It's not, but you're honestly not missing out on too much. He really clams up a lot once he hits about '90-'91 so there's not really many good stories from his career. It goes from "I thought about just jumping off the roof of my high school and ending it all there," to "We had a great match and I'm proud that I won," out of no where. I'm not sure if it's just Japanese cultural differences or because he was still in the business when he wrote it (it was published in 2003). I'm not interested in putting in all the work it'd take to translate a 300 page book, but I hope my write-ups will do a decent enough job of plucking the most interesting parts. I'm also planning on getting Kobashi's two books soon (one from 1999 and one from earlier this year), so I'll do write-ups on them, too.
Zenk is brought up once, but mostly as a friend of Martel and not someone Kawada had too much interaction with. He specifically talks about traveling with Martel and hanging out with him and his wife, but never brings up Zenk other than that one time and to admit he took steroid with Martel and Zenk for about 3 weeks.