In Chamberlain v. Augustine (1916) 172 Cal. 285, the defendant had been significantly involved in one foundry business but wanted to withdraw. (Ibid.) The contract governing the sale of defendant's stock stated defendant would pay $ 5,000 if he engaged in a similar business, although there was no explicit contract provision, which prohibited defendant from engaging in the business. (Ibid.) The California Supreme Court struck down the contract as an invalid restraint on trade; interpreting a former version of section 16600, the court held: "to the extent that the necessity of paying $ 5,000 deters defendant from engaging therein, he would be restrained." (Ibid.) The court looked to the effect of the provision, not to its wording.