滝澤ななみ『新しい日商簿記3級』講談社ビーシー、2020年。
貸借対照表は、借方と貸方に分けられ、借方には資産、貸方には負債と資本（純資産）が記載されます。
損益計算書は、借方と貸方に分けられ、借方には費用、貸方には収益が記載されます。また、収益と費用の差額から当期純利益（または当期純損失）を計算します。
借方と貸方
debits and credits
Debits and credits - Wikipedia
The complete accounting equation based on the modern approach is very easy to remember if you focus on Assets, Expenses, Costs, Dividends(highlighted in chart). All those account types increase with debits or left side entries. Conversely, a decrease to any of those accounts is a credit or right side entry. On the other hand, increases in revenue, liability or equity accounts are credits or right side entries, and decreases are left side entries or debits.
Debits and credits occur simultaneously in every financial transaction in double-entry bookkeeping. In the accounting equation, Assets = Liabilities + Equity, so, if an asset account increases (a debit (left)), then either another asset account must decrease (a credit (right)), or a liability or equity account must increase (a credit (right)). In the extended equation, revenues increase equity and expenses, costs & dividends decrease equity, so their difference is the impact on the equation.
For example, if a company provides a service to a customer who does not pay immediately, the company records an increase in assets, Accounts Receivable with a debit entry, and an increase in Revenue, with a credit entry. When the company receives the cash from the customer, two accounts again change on the company side, the cash account is debited (increased) and the Accounts Receivable account is now decreased (credited). When the cash is deposited to the bank account, two things also change, on the bank side: the bank records an increase in its cash account (debit) and records an increase in its liability to the customer by recording a credit in the customer's account (which is not cash). Note that, technically, the deposit is not a decrease in the cash (asset) of the company and should not be recorded as such. It is just a transfer to a proper bank account of record in the company's books, not affecting the ledger.
To make it more clear, the bank views the transaction from a different perspective but follows the same rules: the bank's vault cash (asset) increases, which is a debit; the increase in the customer's account balance (liability from the bank's perspective) is a credit. A customer's periodic bank statement generally shows transactions from the bank's perspective, with cash deposits characterized as credits (liabilities) and withdrawals as debits (reductions in liabilities) in depositor's accounts. In the company's books the exact opposite entries should be recorded to account for the same cash. This concept is important since this is why so many people misunderstand what debit/credit really means.
