Define the purpose of maintaining subsidiary journal.
The purpose of maintaining subsidiary journals is to facilitate quick, efficient and accurate recording of business transactions. When a business expands and the number of transactions becomes large, it becomes cumbersome to journalise each transaction in a single journal. Therefore, the journal is sub-divided into special journals or subsidiary books.
These subsidiary books are maintained to record all transactions of a similar nature in one separate book. For example, all cash transactions can be recorded in one book, all credit sales in another book, and all credit purchases in yet another book. This arrangement proves to be economical and makes division of labour possible in accounting work, as repetitive transactions can be easily handled by different persons.
Explanation
This answer is derived from the textbook context which explains that subsidiary journals (also called special journals or daybooks) serve multiple purposes: handling large volume of transactions efficiently, enabling quick and accurate recording, allowing similar transactions to be grouped together, and facilitating division of labour in accounting. The context specifically mentions that as business expands, recording all transactions in one journal becomes cumbersome, hence the need for subdivision into special journals.