A breach of contract occurs when a party fails, without lawful excuse, to perform an obligation it undertook under a contract. In Indonesian law the concept is known as wanprestasi, a term derived from the Dutch wanprestatie ("poor performance").
Forms of Breach
Indonesian legal doctrine recognises four forms: not performing at all; performing, but not as promised; performing late; and doing something the contract prohibits.
Default Notice
Before damages can be claimed, the debtor must ordinarily be declared in default. Article 1238 of the Indonesian Civil Code provides that a debtor is in default when ordered to perform by a summons or similar deed, or where the contract itself states that the mere lapse of time places the debtor in default. In practice this summons is called a somasi.
Remedies
The injured party may demand performance, compensation for costs, losses and lost interest (Article 1243 of the Civil Code), termination of the contract, or performance together with compensation. Termination through the court is governed by Article 1266, although many contracts waive it so that termination can take effect by notice.
Distinguished From Tort
A claim in breach of contract rests on an obligation the parties chose to create. A claim in tort (perbuatan melawan hukum) rests on a duty imposed by law, whether or not any contract exists. The two have different elements and must be pleaded with care.