H and W married in 1983. They subsequently had two children and accumulated property together. Separation occurred in 2000. In 2001, W petitioned for dissolution of the marriage. H worked full-time and participated in a stock ownership plan, and contributed to a 401(k) retirement plan. W worked part-time as a nurse at a hospital. She also had a retirement plan through her employer. W's father owned the Santa Barbara house in which the couple lived. H and W contributed some money each month towards use of the house. However, it appears these payments did not cover the mortgage bill or reflect the fair rental value of the property. W is the beneficiary of an irrevocable trust. Her father is the trustee. w's father gave the couple a 100 percent ownership interest in the Santa Barbara house. This transfer occurred incrementally over several years. At some point during this process, W's father asked the couple to convey the house to the trust. They agreed. Hence, in two transfers occurring in late 1996 and early 1997, the couple signed grant deeds giving the trust a 100 percent ownership interest in the house. H maintained that he acquired a community property interest in the house. H successfully moved before trial to join the trustee, W's father, as a party. while trial was underway, H settled all claims against the trust for an agreed-upon amount. The court promptly dismissed the trustee from the case with prejudice. H then testified that an oral agreement between the parties changed the community character of both the house and his retirement accounts. In 1996, when the couple signed the first deed in favor of W's trust, H agreed to forgo any community interest in the house and W agreed to forgo any community interest in his retirement accounts. W said she would sign a writing transforming H's retirement accounts into his separate property. That was never done. W denied making any promise. The court reasoned that section 852(a)'s writing requirement is subject to implied exceptions that traditionally have been applied in other statutory contexts. Thus, H's act of deeding the house to the trust constituted “part performance” of the oral transmutation agreement he described and permitted its enforcement against W. The Court of Appeal affirmed the judgment. W appealed.