Any experience you have that does not bring you peace, you failed to accept. To the degree you feel removed from a peaceful state, you have a list of rejections.
In Bushido, murder meant killing outside of the boundaries of the order, a dishonourable killing. The acts of the Ninja were considered murder.
To kill another in battle is ok? Yes, except for the weak or the unprepared. Thus why Ninjas were seen as so dishonourable. They held to a different creed. A sect of monks who immigrated from China and settled into the Iga and Koga mountains.
If the acts of the Ninja were dishonourable, why were they used at all? Would it not be a dishonour to those who hired them? Yes, it would be dishonour to those who hired them in the code of Bushido. But Buddhists often keep a distant relationship with the local government, and the sect in question held a dim view of the social order as it had degenerated. The Ninja were not always a part of Japanese culture, not in the common capacity, thus the eight pointed star they used was a symbol of the eightfold path. Basically calling the targeted Samurai a traitor as the Ninja weren’t acknowledgers of the Shinto doctrine. The monks had carried with them some of the practices of Bon, the Chinese equivalent of Shintoism.
Isn’t the star a weapon? The star could injure, but couldn’t kill. They used it to aggravate their target, and the Ninja also dishonoured the Samurai.
Was it dishonourable to be injured? No, but it was considered mockery. The Samurai were insulted by the indirect attack, but a Samurai’s sword was a sacred relic handed down along the line and considered to house a part of the spirit of all the ancestors. If a Ninja captured one they would break it and retemper it, both making it suit their own needs and turning the relic against the Samurai. Honestly at first the Ninja were commoners who sided with the mountain Buddhists. But later Samurai who saw that their lord and their society could be corrupt, would in a sense convert also.
Your thoughts are welcome. Be well friends.