Haw. Rev. Stat. § 560:2-502: Execution; witnessed wills; holographic wills.

(a) Except as provided in subsection (b) and in sections 560:2-503, 560:2-506, and 560:2-513, a will must be:

(1) In writing;

(2) Signed by the testator or in the testator's name by some other individual in the testator's conscious presence and by the testator's direction; and

(3) Signed by at least two individuals, each of whom signed within a reasonable time after the individual witnessed either the signing of the will as described in paragraph (2) or the testator's acknowledgment of that signature or acknowledgment of the will.

(b) A will that does not comply with subsection (a) is valid as a holographic will, whether or not witnessed, if the signature and material portions of the document are in the testator's handwriting.

(c) Intent that the document constitute the testator's will can be established by extrinsic evidence, including, for holographic wills, portions of the document that are not in the testator's handwriting.