There are several reasons why Akechi Mitsuhide rebelled and here is a list.
- Nobunaga treated Mitsuhide as an outsider
- Did not receive rewards
- Always insulted
- The murder of his mother (still debated)
- Nobunaga jealous of Mitsuhide's poetic talent
Mitsuhide was an outsider. He was not from the Owari band of warriors. He probably came from Mino. After Nobunaga took full control of Owari in 1559, most or all of the rebellions came from outsiders.
Nobunaga did experience constant betrayal in the 1570s. Matsunaga Hisahide in 1572 and 77, Araki Murashige in 1578. Then you have Mitsuhide in 1582. This constant betrayal made Nobunaga's authority a dictatorship. It was human nature to make sure he had total control of his vassals. It was only a matter of time for one to say enough is enough. Mitsuhide had enough of Nobunaga's brutal dictatorship because I think he received most of criticism.
Again, Japan lost a great man. If Nobunaga lived for at least another ten years, Japan would be a very different country for sure.
I plan to write more on the Honnoji later this month.
Nobunaga no tame!