You'd be surprised how much of the western notion of bushido was popularized by romantic old homosexual nationalists in an age when samurai were already more or less obselete...
Needless to say: warfare is warfare. And while honor was valued, to a point, there were plenty of dirty-dealings (and quite a few people who found a path to glory through trickery... and were celebrated for it in literature).
Samurai didn't fight wars by standing in perfect little lines and facing each other one on one with a referee.
Don't buy the western romantic notion of perfect Japanese honor. Most of it's BS :P
The CONCEPT of honor is just as valued today as it ever was... evidenced by our love for notions of old-time chivalry and samurai codes when there isn't a lot of actual history to hold up that either was much more than ideological largely retroactive romanticism.
There was a code of Bushido... but it was, for most, something legendary and lofty to aspire to, not a strict way of conducting warfare. Ironically it became the most popular and rigid in times of peace (thanks to the gentrification of the samurai class). Bushido is also open to interpretation... which might explain how we went from "calling out your opponent by name" to sneak attacks, fighting to the last man, and kamikaze pilots in WWII (something few would consider either honorable or positive).
Honor is a lovely idea... but it's never been something EASY to come by, or widely practiced to perfection.
Yoshitsune's victory at Yashima was not honorable (though it was brilliant), Yoritomo's slaughtering his wife and children was downright despicable, Nobunaga's pillaging and razing Kyoto was rotten as hell. Annexing Korea was not honorable, the rape of Nanking was not honorable, sneak attacking Pearl Harbor was not honorable... And yet, all the participants became heroes (some more controversial than others).