Like Henshin, this phrase is often shouted by transforming heroes when they transform. This is the kanji for Chakusou flipped around.
While Henshin means that the body is changing, Souchaku means "Equipping" or "Installing". Essentially it's more putting on armor than
The ChouSeiShin Series all use Souchaku when they transform.
Their spiritual successors, the Tomica Hero series flip the kanji around and they use Chakusou to transform.