Although he did not use the term, he essentially prescribed a technique similar to a post-closing trial balance.
[1] The primary purpose of preparing a trial balance is to ensure the accuracy of an entity's double-entry bookkeeping system.
This error must be found before a profit and loss statement and balance sheet can be produced.
The trial balance is a part of the double-entry bookkeeping system and uses the classic 'T' account format for presenting values.
The resulting opening balance for the new accounting period will still have columns of equal sum totals.