It's in the order of the Japanese alphabet, 
starting:

a,i,u,e,o
ka,ki,ku,ke,ko
sa,shi,su,se,so
ta,chi,tsu,te,to
na,ni,nu,ne,no
ma,mi,mu,me,mo
ya,yu,yo
wa,wo
ra,ri,ru,re,ro

You have to know the Japanese title to know 
which one to look in.