Explanation

Goods bought on credit are first entered in the purchases day book (also called the purchases journal or bought day book). This is a book of original entry specifically for recording credit purchases.

When a business buys goods on credit, the transaction is first recorded in the purchases day book with details like date, supplier name, invoice number, and amount. At the end of the period, the total is posted to the purchases account in the ledger.

The cash book is used for cash transactions, not credit purchases. The journal proper is used for transactions that do not fit in other books of original entry, such as correction of errors or opening entries.

The sales day book is used to record credit sales to customers, not purchases. Each type of transaction has its own book of original entry to organize records and make posting to ledgers easier.