Where is the onus on a check?

Could you please elaborate on the concept of "onus" in the context of a check? Are you referring to the responsibility or obligation placed on a party involved in the check transaction? If so, is it the responsibility of the issuer to ensure the check is valid and funds are available, or the responsibility of the recipient to verify the authenticity of the check before depositing it? Additionally, is there a specific legal framework that outlines the onus in regards to checks, and how does it differ from other forms of payment?