Blockchain systems are increasingly integrating time as a fundamental layer to enhance their functionality and reliability. The concept, termed the "fifth layer," emphasizes the importance of temporal consistency over code complexity. In the Origin Layer, platforms like IOPn_io and Artery_Chain focus on identity and time synchronization, ensuring system continuity and trust with minimal time deviation. The Operation Layer sees projects like SolsticeFi and VdexFinance using time cycles to adjust risk models and bind execution times to transactions, respectively, enhancing transparency and efficiency. The Memory Layer, represented by DeSci__News, aligns data with timestamps, transforming historical records into dynamic proofs. Meanwhile, the Expression Layer, with platforms like ValanniaGame and xeetdotai, uses time to predict economic behaviors and filter signals, fostering a decentralized future that values rhythm and coherence over speed.