The postman just delivered a new edition of the O-umajirushi, a 17th century book on samurai heraldry, post-sengoku era, but still rather interesting even for those of us fluent in Japanese. The book is in full colour and brings us the six rolls or volumes of the original annotated and translated in English. It started as a kickstarter project by one Xavid Pretzer and comes both in hardcover or softcover version.
More info can be found on this site: http://o-umajirushi.xavid.us

O-umajirushi was compiled in the period 1624-1644, so shortly after the sengoku jidai, but of course the heraldry of the daimyô and clans of that time would be the same as say at the battle of Sekigahara and before. So it is still a very valuable source for the heraldry of the sengoku era. With post-sengoku I referred to the original book, not to its contents, sorry for the confusion.
cheers