The binding legal principles are: (1) Fault is not a requirement for a claim for damages based on breach of contract. (2) The general rule that impossibility of performance caused by vis major or casus fortuitus excuses contractual performance does not apply where the impossibility is self-created through the defendant's fault or failure to take reasonable steps to prevent or remove the impossibility. (3) In assessing whether impossibility is self-created, courts must examine whether the party had available means to prevent or remove the obstacle and whether failure to use those means constitutes fault. (4) Once a land claim is published under s 11(1) of the Restitution of Land Rights Act, development of the land is prohibited without proper notice under s 11(7), and reasonable steps such as s 34 applications may be required to discharge contractual obligations. (5) The onus of proving that mitigation measures (such as obtaining bridging finance at particular interest rates) were unreasonable rests on the party asserting unreasonableness, who must show that less expensive alternatives were available. (6) Interest on unliquidated debts runs from the date of service of demand or summons (whichever is earlier) per s 2A(2)(a) of the Prescribed Rate of Interest Act 55 of 1975, unless there is just reason to depart from this rule under s 2A(5).