In 1957, Oglebay Norton Co. (Oglebay) (plaintiff) entered into a long-term contract with Armco, Inc. (Armco) (defendant). Oglebay agreed to meet all of Armco’s iron ore shipping needs in the Great Lakes, and Armco agreed to pay a flexible shipping rate, set according to primary and secondary market factors described in the contract. The parties periodically extended the contract, most recently through 2010. However, between 1983 and 1985, the market changed, and shipping rates were no longer made public. As a result, the parties could no longer rely on the primary and secondary market factors in the contract for determining the shipping rate. The parties mutually agreed on a rate in 1984, but they were unable to agree thereafter. Oglebay filed for a declaratory judgment to set the shipping rate, and the parties continued to perform pending the court’s decision. In August 1987, Armco filed a counterclaim seeking to have the contract declared no longer enforceable. The evidence presented to the trial court demonstrated, among other things, the parties' business relationship and intent to be bound to the contract, as well as a range of shipping rates in the industry. The trial court issued a declaratory judgment in November 1987 setting the shipping rate at $6.25 for 1986, and ordering the parties to mutually agree on, or submit to mediation to determine, the shipping rate through 2010 when the contract concluded. Armco appealed. The court of appeals affirmed the trial court. The case was certified to the Supreme Court of Ohio.