Record splitting lifts CBDC transaction capacity to 6,000 TPS
The Bank of Japan found no fatal technical barriers to central bank digital currency deployment after testing an experimental platform up to 50,000 transactions per second. The pilot evaluated single-account bottlenecks, post-quantum security, and inter-ledger consistency.
Breaking the account bottleneck
Performance tests on the Bank of Japan's experimental platform confirmed that record splitting can increase single-account throughput from 50 to 100 transactions per second (TPS) up to 6,000 TPS per account.
Further computational analysis indicated that splitting an account into 600 records could enable 18,500 TPS.
In a mixed workload trial combining 10,000 update transactions and 40,000 balance inquiries, the system processed 50,000 TPS.
The Bank evaluated these metrics against a full social implementation benchmark of 500,000 TPS, comprising 100,000 updates and 400,000 inquiries.
Although server and network resource consumption was substantial, the experiments identified no insurmountable technical knockout factors for scaling up throughput.
From seven working groups to three pillars
Beyond core ledger testing, the Bank explored post-quantum cryptography, offline transactions, and interoperability with private money.
The CBDC Forum, established in July 2023 with 64 private firms, convened 84 meetings featuring presentations from 163 companies.
To focus future work as issuance considerations advance, the Bank is reorganizing the Forum's original seven thematic working groups into three structured discussion groups covering architecture, new technologies, and the CBDC ecosystem.
Feasible in the lab, undecided in practice
The pilot demonstrates that retail throughput targets are technically achievable with database record splitting.
Yet the massive resource overhead and multi-ledger reconciliation challenges will make real-world deployment costly.
Engineering feasibility is now established, but the political justification for issuance remains unresolved.