That is a Japanese family crest, but there are so many you would be very lucky if one of our members were to recognize that one. You can learn moe abut family crests in general at this iste:
 
http://www.japan-society.org/crest_jssdt.html
 
I am sure with a good google search you could find other sites in Japanese and you may find a match for the one you're asking about. Or you could just ask the site's admin what family it represents.
 
A tatoo using a family crest is something to give serious thought to. I hear a tatoo is painful to remove, and you could get very unlucky and run into a family member belonging to that crest and be asked to remove the tatoo. Maybe not, but life has a strange way of messing with people. One never know.
 
EDIT by ManyQs
I forgot the reference to the book. That's probably your solution. Write the author.

As ManyQs says this is a "kamon" or family crest. There are books and sites about kamon and it is certainly possible to look it up. It looks like birds arranged in a circle, probably cranes (tsuru) as they feature so much in Japanese folklore.
 
This page has some kamon featuring tsuru. None the same as yours, but some similar near the bottom (in Japanese):
http://www.otomiya.com/kamon/animal/tsuru.htm
 
There's tons more kamon on this site (also in Japanese):
http://www.asgy.co.jp/kamon/kamon.html
 
Something I just learned on there is that a family name, say Suzuki, can have lots of different crests and the same crests seem to be used by different families, though one tends to be the most popular for any given family name. The site has the most popular kamon for the most common names. It also has the most popular altogether, and yours isn't in the Top 100.
 
This page has the kamon of some of the most famous historical figures:
http://www.asgy.co.jp/kamon/famous/famous.html
 
Hagakure, as you probably already know, is a type of bushido code, a book that describes the samurai way of life etc and was written in the mid-Edo period by Yamamoto Tsunetomo. It's similar in that sense to the famous Book of Five Rings, by Miyamoto Musashi. All the info you could possibly need on "Hagakure: The Way of the Samurai" on Amazon:
http://www.amazon.com/exec/obidos/ASIN/4770011067/qid=1123678433/sr=2-1/ref=pd_b bs_b_2_1/104-6253193-1381569
 

 
I thought I was finished writing this, when I noticed that the kamon on this edition on Amazon is completely different to the one  linked by remform. This one is the biohazard symbol in a circle! So maybe the kamon on the book is either a) made up or b) not relevant to anything specific, just randomly chosen.
 
This is quite an interesting little hunt...

I'm on my way out the door and will be away for the wekend. I'll try and look into this when I get back. Meanwhile, anybody else who can offer some insight?

I recently got a book by the Matsuya Piece-Goods Store, called "Japanese Design Motifs-4,260 Illustrations of Japanese Crests".  I will quote and summarize a few areas of the book below:  
 
Japanese crest date back to the 11th century and were used to distinguish rank with the courtiers to the Imperial court.  Common symbols back than included the Crane-English or Tsuru-Japanese.  
 
At the end of the 12th century the warrior class took over and used their own emblems.  The courtier and his household used the same crest but the warrior's allowed the use of different variations of crest.    
 
The large circle around the cranes is something that became more common in the years after World War II.  It became more popular in formal dress than distinguishing sides.
 
So basically out of this book 4,260 variations (in search of my own family crests) I did see something close to our family crest but did not see the exact match.  Good luck in finding the family that matches this crest!  
 
Jae

It looks like the image mentioned in the first post of this thread isn't there anymore. So are you looking for the symbol on the cover of the Hagakure book that's shown above? 'Cos I think this is different from the one the OP was talking about...
 
If you have the time, you could look through the 4,000 or so kamon on this website:
http://www.asgy.co.jp/

The crane francois mentioned in the pervious post:
It is three cranes interlinked. In Japanese that is Kourinkanawazuru.   "kourin"is that style of crane without any feather detailed or drawn on it. "zuru" means crane. I don't speak Japanese, so I don't know what "kanawa" means. Cranes are a symbol of longevity, so they are very popular crests.
 
The "hazard symbols" is not that at all, but rather three "dai" kanji in a circle. It is not an uncommon crest. Dai means big, and was used by families hoping for success and good fortune.
 
A note on crests:
Originally crests were just picked randomly by the family who bore them. Signs of good like or symbols representing the family name were often picked.  They later became inherited and certain rulers would ban all other from using the crest they picked. Younger sons and loyal retainers might be granted the use of a slightly form of the lord's crest. In modern times (at least where I live) most people no longer know their family crest. If you want a tatoo of a crest, I would suggest adopting a crest for a good reason (NOT "its pretty") and using that one.  
 
The best English language resource on kamon is Family Crests of Japan, published by Stone Bridge Press.

Quote from Yuki on 06/19/09 at 22:08:20:

Thanks for the informative post. Kanawa (金輪) means "metal ring/hoop/band."