He was no idiot

Here is another article on Nobunaga explaining if he was a fool.  He was not an idiot and the article in Japanese gives examples why he was not an idiot.

https://bushoojapan.com/bushoo/oda/2019/02/05/120032

He was extremely different from other Sengoku daimyo during his time.  Often riding horses, swimming in rivers during the summer, practicing the rifle and bow, engaged in falconry, and studying the art of war when necessary.  This had a huge impact on Nobunaga since it was the building block to his success.

While out in the countryside with his pages, mock battles would include long spears, which he quickly adopted in his army.  Riding his horse daily included surveying the land.  He knew the geography of Owari and its surrounding borders well.  This would help him during the Battle of Okehazama.

People often called Nobunaga an idiot probably because of jealousy.  He was different from the rest, promoted on merit, not on family lineage.  He hired outsiders such as Hideyoshi, Akechi Mitsuhide, and the Men of the Fields to do the dirty work for him.  Only two people knew the greatness of Nobunaga when he was young, Saito Dosan and Hirate Masahide.  His father Nobuhide knew Nobunaga's capability as well.

Nobunaga no tame!