Pappy, take a look at that glove....
![Shocked :o](http://www.primitivearcher.com/smf/Smileys/default/shocked.gif)
The samurai used the kyudo shooting style and I'm sure they weren't shooting target arrows.
![Wink ;)](http://www.primitivearcher.com/smf/Smileys/default/wink.gif)
Anyway, I think the holding of the second arrow is a result of the two-shot round in target shooting. I don't think I've ever seen samurai holding a second arrow (in illustrations) when fighting.