I am trying to recall a martial arts movie, likely chinese/Hong Kong but not 100% sure. I think I ran into it because of a small interest in Master of the Flying Guillotine and wanted more over-the-top 70s ninja or wuxia films that throw a lot of unbelievable stuff at you.
I figure it must be from the 70s. The one thing I recall is an early fight among some trees, perhaps adjacent to a field, where the hero(es) are attacked by three(?) agile assassins, I think wearing large brimmed hats. They can leap from tree to tree and at one point, one horrifyingly spits a large volume of acid or something from their mouth with great force. The other ones maybe also have distinctive supernatural powers.
I figure this sequence is distinctive enough to get an ID, if not I can also investigate any martial arts movies with screwball superpowers in it (like the yoga master from flying guillotine).