The 1575 Battle of Nagashino resulted in the eventual end of the Takenda clan during the sengoku jidai in Japan. In the movie "Kagemusha", the Takeda cavalry charges guns and is devastated. The wikipedia article claims a similar scenario. However, I read (I don't recall where) that the actual battle involved Takeda sending sappers in "penny packets" against prepared positions looking for a non-existent weakness in the Oda defenses. After frittering away their sappers, Takeda could not overcome the prepared positions and was defeated. Is there a definitive account of the battle or any strong evidence for how the actual battle occurred?
The Takeda attack destroyed the first palisades, but was unable to break through much further. Their army ended up smashing themselves against the second line. I can see how that could be described as "sappers" failing before the Oda defences.
On the other hand, the battle was most likely not a cavalry charge. Despite popular mythology, riders made up less than 10% of the Takeda army. Whether the clan even conduct mounted combat at all is strongly disputed; but in either case, clearly Takeda Katsuyori did not have enough cavalry for the sort of sustained combat that Nagashino is supposed to have been.
As a side note, at Nagashino the Takeda army numbered only 15,000. They assaulted a dug in Oda-Tokugawa formation of 38,000 strong, and was routed after a vicious 8 hour battle. I feel there's a tendency to look too hard for reasons behind the Takeda defeat, when sometimes god is simply on the side of big battalions.