HRS § 571–3 (2006). “[E]quity regards the substance rather than the form.... Equity goes behind the form of the transaction in order to give effect to the intention of the parties....” Schrader v.Benton, 2 Haw.App. 564, 566, 635 P.2d 562, 564 (1981) (quoting Lord v. Lord, 35 Haw. 26, 39 (Haw.Terr.1939)) (internal quotation marks omitted). The promissory notes were part of an overall structure intended to pay Joel the entire amount of the Retention and Longevity Bonuses up front while ensuring that he would not have to pay taxes on those lump sums.