A base chain is the primary blockchain that serves as the foundation for a network. It handles core functions like transaction validation, consensus, and security. In many ecosystems, additional layers or side chains may be built on top of a base chain to improve scalability, enhance privacy, or enable specific functionalities.

These layers can interact with the base chain while benefiting from its security and decentralization features. An example of a base chain is Bitcoin, which processes all transactions and ensures security through its proof-of-work mechanism. Ethereum also acts as a base chain, allowing developers to create decentralized applications and smart contracts.

The efficiency of a base chain is crucial for the overall performance of the entire network. A strong base chain can support many applications while maintaining high levels of security and decentralization.