Ohio Revised Code Title LVII. Taxation § 5731.07

(A) The value of the gross estate shall include the value of all property, to the extent of any interest therein of which the decedent has at any time made a transfer, except in the case of a bona fide sale for an adequate and full consideration in money or money's worth, by trust or otherwise, if both of the following conditions exist:

(B) “Reversionary interest” includes a possibility that property transferred by the decedent may return to him or to his estate or become subject to a power of disposition by him and its value shall be determined immediately before the death of the decedent by the usual methods of valuation, including the use of tables of mortality and actuarial principles, under rules and regulations prescribed by the tax commissioner.