The Tax court disallowed a charitable contribution deduction in 1981 for two checks dated in 1980 but allegedly delivered to the charity in early 1981, because the taxpayer could not prove that the checks were in fact delivered in 1981. The Court relied on the well-established rule that checks constitute a charitable contribution only upon delivery (or mailing) to the charity. Marshall v. Commissioner, T.C. Memo. 1986-582.