If you go to:

http://books.google.com/

and enter various Japanese fishing terms you can find several Japanese language Tenkara or Keiryu fishing books in the search results list that have a ?look inside? feature. It will say ?preview? just below the website address if that book has the look inside feature. The only additional thing I have noticed is that if I find the same book using a different Japanese phrase to do the search often I will find that when opened the book I can view different pages. But not always - sometimes only the same pages are displayed.

If you find a book with a lot of pictures or diagrams they can be fun to look at even if you can?t read most of the text. Additionally when you look at a particular title if you are interested in ordering it there are several links in the top left corner to book sellers where you might be able to order the book. I found two books that did not have the look inside feature, but the titles and description was interesting so I ordered them when I found they were listed on Amazon. Details about them are listed below.

Good search phrase to use are:
テンカラ釣り Tenkara Fishing
渓流釣り Mountain Stream (Keiryu) Fishing
毛鉤釣り Kebari Fishing
山釣 Mountain Fishing
本流テンカラ Mainstream Tenkara
テンカラ竿 Tenkara rod
海川釣り sea river fishing *
ヘラ釣り Hera (Carp) Fishing.
タナゴ釣り Tanago Fishing.

If the search results list shows a page number when you open that book it will open to that page and the search term will be highlighted in yellow on every page you look at that has the same phrase. However, sometimes the page number listed will be blocked from viewing. And sometimes you open a book that had an interesting front cover or title, but when you open it you may find it is mostly text. Not much fun if you can not read Japanese.

The Tanago Books were some of the most fun to look at.

* When I first found 海川 I thought it was the name of a river near Nagano, but after a lot of looking for a river with that name I have pretty much decided it is a name for any river that empties into the sea. While searching the term 海川 I found this interesting 2012 Yoshida blog post.
テンカラの川と海 = Sea and River Tenkara.

先ずは「川」。First is the River.
そしてこちらは「海」。 一年中テンカラを楽しみ And this the sea. To enjoy Tenkara year round.

http://yoshidakebari.jugem.jp/?eid=726

Anyway, using the books.google search I found two Japanese language Tenkara books that did not have the look inside feature, but I ordered them and they are very nice books with a lot of diagrams on most pages of fishing gear, fishing techniques, and kebari.

本流テンカラ読本:
本流テンカラを始める人のために
Author 。博?渡辺
Mainstream Tenkara reader:
For those who start the mainstream Tenkara
Author. Hiroshi Watanabe
http://ecx.images-amazon.com/images/I/91-vxjGdDML.jpg

It's a good book. Pictures and or diagrams on almost every page. Diagrams with short captions that I will be able to figure out. And it was kind of fun because it was published the same month and year my son was born, March 1996.

The other book is:

正統テンカラ逆さ毛バリ
右田政夫
Legitimate Tenkara upside down fly (reprint)
Author: Migita Masao

http://homepage3.nifty.com/somame/c-seitotenkara2.htm

It's pretty good too. Not quite as many diagrams and pictures as the Watanabe book, but almost as many pictures and diagrams as the Watanabe book and it shows several kebari I want to see if I can tie similar ones. He is credited with spreading the popularity of sakasa kebari nationwide in Japan.

Maybe you will enjoy looking at some of the Japanese language fishing books.

D