Young Guitar
Monthly guitarist magazine, started in May 1969. The magazine is published by Shinko Music Entertainment (シンコーミュージック・エンタテイメント) (wikipedia)
2009 July
No. 7 Issue 575
Frank Zappa
By Umemura Shoji (梅村昇史), Shige, Young Guitar magazine
pp 48-54
TAN Mitsugu:
Includes two short interviews with Dweezil Zappa and Mike Keneally.
The former was conducted by Fukuda Masami (福田真巳) with translator
Kawahara Mariko (川原真理子), while the latter was done by an editor
from Young Guitar.
A quote from the interview with Keneally:
"Frank gave me a chance to improvise, approximately in each
three shows, but I was still young at the time, struggling to
play the most effective phrases. As a desperate effort, I played
guitar with one hand and keyboard with the other hand. And it
made Frank cracking up, and then he encouraged me, saying "do
it more!". So it became my own style of entertainment that I
still keep doing these days."