HashToken was deployed on June 17, 2016, making it the first Ethereum token to implement a self-limiting proof-of-work model. This groundbreaking contract introduced the revolutionary concept of exponentially increasing mining difficulty, where each successful mint makes subsequent tokens 1% progressively harder to mine, creating natural scarcity through computational work. Also built and based on the StandardToken code, it implements an early ERC-20 interface, allowing it to retain compatibility with modern exchanges without needing an assisting wrapper. It stands as the oldest trustlessly distributed token on Ethereum to feature this early ERC-20 architecture.