Japanese Backstab has similar text ("使うごとに+:hocho:1") (Add 1 on each use) to Japanese Electromagnet ("使うごとに+2") .
However, the behavior is different.
Electromagnet damage is increased only when Electromagnet is used, but Backstab damage is increased when other equipment is used.
This difference cannot be read from the Japanese text.
Japanese Backstab should be "装備を使うごとに+:hocho:1" (Add 1 on each equipment use).
Japanese Backstab has similar text ("使うごとに+:hocho:1") (Add 1 on each use) to Japanese Electromagnet ("使うごとに+2") . However, the behavior is different. Electromagnet damage is increased only when Electromagnet is used, but Backstab damage is increased when other equipment is used. This difference cannot be read from the Japanese text.
Japanese Backstab should be "装備を使うごとに+:hocho:1" (Add 1 on each equipment use).