The presently-disclosed solution provides cross-ledger transfers between distributed ledgers to achieve highly-scalable transaction throughput. Disclosed are methods and instruction code for writing a cross-ledger transfer in a way that effectively transfers value from a source distributed ledger to a target distributed ledger while preventing double spending of the value. This results in the transformation of the ledgers in that the total value in the source ledger is decreased by the transferred value while the total value in the target ledger is increased by the same amount. Also disclosed are system architectures that utilize cross-ledger transfers between multiple distributed ledgers to achieve highly-scalable transaction throughput. Also disclosed are computer apparatus configured to implement cross-ledger transfers between distributed ledgers. Other embodiments and features are also disclosed.