Payments - Introduction / Learning brief
Japan's BOJ-NET and the Zengin System
Your notes
In simple terms / 01
What this means in plain language
Japan settles large-value yen payments gross in the Bank of Japan's BOJ-NET, while the Zengin System clears domestic retail credit transfers and settles their net positions across accounts at the Bank of Japan — with large items diverted to BOJ-NET.
Complete lesson / 02
Understand the full idea, step by step
Two yen payments leave two banks in Tokyo on the same morning. One is a JPY 300,000,000 obligation between two banks; the other is JPY 50,000 of rent between two people. They travel different rails, settle in different ways, and finalize at different moments — yet both come to rest across accounts held at the same place: the Bank of Japan. Japan runs a deliberate split between large-value and retail payments, and this lesson is about where the line falls and why.
Japan's two rails at a glance
- BOJ-NET
- The Bank of Japan's real-time gross settlement (RTGS) system for the yen
- Zengin System
- The interbank clearing network for domestic retail credit transfers, operated by Zengin-Net
- How BOJ-NET settles
- Each large-value payment settles individually and immediately across current accounts at the Bank of Japan
- How Zengin settles
- Retail transfers are netted, and the net positions settle across accounts at the Bank of Japan
- The dividing line
- Payments of JPY 100 million or more are diverted to RTGS in BOJ-NET
- Settlement agent for both
- The Bank of Japan, across banks' current accounts on its books
One central bank, two ways of settling
Both rails end at the Bank of Japan, but they get there differently. BOJ-NET is the large-value engine: it takes each accepted funds-transfer message and settles it in full, on its own, the moment there is cover — no batching, no waiting for other payments. The Zengin System is the retail engine: it collects the day's ordinary credit transfers, works out what each bank owes each other on a net basis, and then settles those net amounts across the banks' current accounts at the Bank of Japan. The practical rule that ties them together is a threshold. A domestic transfer of JPY 100 million or more does not ride the retail net cycle at all — it is diverted to real-time gross settlement in BOJ-NET, so the largest, most exposure-heavy payments finalize one by one rather than sitting inside a net position.
Real-time gross settlement (RTGS) — each payment settles individually and immediately, in full or not at all
In an RTGS system, every accepted instruction settles on its own, the moment cover is available, in central-bank money. There is no netting off against other payments — hence gross — and no batch window to wait for — hence real time. BOJ-NET is the yen's RTGS system: the Bank of Japan debits the sending bank's current account and credits the receiving bank's, individually and finally, for each large-value transfer. Because settlement is in full or not at all, a payment the sender cannot cover is not settled partially; it waits.
Deferred net settlement (DNS) — obligations are cleared continuously but settled net at a later point
The Zengin System clears retail transfers as they arrive — routing details on to the receiving bank so beneficiaries can be paid — but the banks do not move central-bank money for each one. Instead, the Zengin Center adds up the day's transfers and calculates each participant's single net position, and those net amounts settle later across accounts at the Bank of Japan. Clearing is continuous; settlement is deferred and netted. This is efficient for large volumes of small payments, but it means the interbank money moves after the beneficiary has already been credited.
You may be wondering: if the retail leg only settles net later, how does Arjun get his rent right away?
Nordbank credits Arjun on trust. Having received the routed Zengin transfer, it makes the JPY 50,000 available to him straight away, expecting the interbank leg to settle net across the Bank of Japan later that day. That trust is exactly why the JPY 100 million threshold exists: for small retail sums the risk between banks is manageable, but for very large payments it is not, so those are pushed into BOJ-NET where each one settles with finality before anyone is relying on a promise.
The large-value payment: gross, in real time
- MESSAGE
Bank Alfa submits a BOJ-NET funds-transfer message for JPY 300,000,000 to Nordbank. This is an instruction — the money has not moved yet.
- VALIDATION
BOJ-NET checks that Bank Alfa's current account at the Bank of Japan holds enough to cover the payment in full, because an RTGS system settles each transfer entirely or not at all.
- SETTLEMENT
The Bank of Japan debits Bank Alfa's current account and credits Nordbank's, individually and immediately, in central-bank money. Settlement is final at this moment.
- NOTIFICATION
BOJ-NET confirms to Nordbank that the funds are on its current account and the settlement is final.
- LEDGER
Because the interbank leg has already settled with finality, Nordbank books the JPY 300,000,000 credit to the beneficiary without waiting for any netting cycle.
Read the steps as text
- 01MessageBank Alfa submits the BOJ-NET transferBank Alfa (sending bank) → BOJ-NET Funds Transfer System · BOJ-NET funds transfer
Bank Alfa sends a real-time gross settlement (RTGS) funds-transfer message for a high-value yen obligation to Nordbank. This is an instruction — the money has not moved yet.
- 02ProcessingBOJ-NET checks the current-account balanceBOJ-NET Funds Transfer System
BOJ-NET checks that Bank Alfa's current account at the Bank of Japan holds enough to cover the payment, because an RTGS system settles each transfer in full or not at all.
- 03SettlementThe Bank of Japan settles the payment in real timeBank Alfa (sending bank) → Nordbank (receiving bank)
The Bank of Japan debits Bank Alfa's current account and credits Nordbank's, individually and immediately in central-bank money. Large-value payments of JPY 100 million or more settle this way.
- DR Bank Alfa's current account at the Bank of Japan — JPY 300,000,000
- CR Nordbank's current account at the Bank of Japan — JPY 300,000,000
- 04MessageNordbank is told the payment has settledBOJ-NET Funds Transfer System → Nordbank (receiving bank)
BOJ-NET confirms to Nordbank that the funds are on its current account at the Bank of Japan and the settlement is final, with the details of the payment.
- 05PostingNordbank books the fundsNordbank (receiving bank)
Because the interbank leg has already settled with finality across the Bank of Japan's books, Nordbank can record the credit on its own ledger without waiting for a netting cycle.
- CR Beneficiary's account at Nordbank — JPY 300,000,000
The retail payment: cleared now, settled net later
- CUSTOMER
Riya instructs Bank Alfa to pay Arjun JPY 50,000 by domestic credit transfer. On its own the instruction carries no funds.
- LEDGER
Bank Alfa accepts the instruction and debits Riya's account. Her money has left, but no money has yet moved between the banks.
- CLEARING
Bank Alfa sends the transfer through the Zengin System, which routes the details on to Nordbank.
- LEDGER
Nordbank credits Arjun so he can use the JPY 50,000, trusting that the interbank leg will settle net later that day.
- SETTLEMENT
The Zengin Center calculates each bank's net position, and those nets settle across the banks' current accounts at the Bank of Japan — only now has interbank money moved.
Read the steps as text
- 01MessageRiya instructs the transferRiya (payer) → Bank Alfa (sending bank)
Riya asks Bank Alfa to pay Arjun by a domestic credit transfer. The instruction is a request to move money; on its own it carries no funds.
- 02PostingBank Alfa debits Riya's accountBank Alfa (sending bank)
Once Bank Alfa accepts the instruction it books the debit. Riya's money has left her account, but no money has yet moved between the banks.
- DR Riya's current account at Bank Alfa — JPY 50,000
- 03MessageBank Alfa sends the transfer through the Zengin SystemBank Alfa (sending bank) → Zengin System (Zengin-Net)
Bank Alfa submits the transfer to the Zengin System, the interbank clearing network run by Zengin-Net, which routes the details on to the receiving bank.
- 04PostingNordbank makes the funds available to ArjunNordbank (receiving bank)
Having received the routed transfer, Nordbank credits Arjun so he can use the money, trusting that the interbank leg will settle later that day.
- CR Arjun's current account at Nordbank — JPY 50,000
- 05Clearing obligationThe Zengin Center calculates each bank's net positionZengin System (Zengin-Net)
The Zengin Center adds up all the day's transfers and works out one net amount each participant owes or is owed — these are obligations, not yet money.
Netting produces who-owes-whom. The banks do not have their money yet — that only happens at settlement across their Bank of Japan accounts.
- 06SettlementNet positions settle across accounts at the Bank of JapanBank Alfa (sending bank) → Nordbank (receiving bank)
The net positions settle across the banks' current accounts at the Bank of Japan, which finalizes settlement. Only now has money moved between Bank Alfa and Nordbank.
This retail transfer is well under JPY 100 million, so it settles on a deferred net basis. A transfer of JPY 100 million or more would instead settle one-by-one in real time (RTGS) in BOJ-NET.
- DR Bank Alfa current account at the Bank of Japan — JPY 50,000
- CR Nordbank current account at the Bank of Japan — JPY 50,000
COMMON CONFUSION
“BOJ-NET and the Zengin System are competing networks, and a bank picks whichever it prefers for a given payment.”
They are not competitors; they are two layers of one national arrangement, and the treatment is chosen by the payment, not by preference. Retail credit transfers clear through the Zengin System and settle deferred-net; large-value payments — JPY 100 million or more — are diverted to real-time gross settlement in BOJ-NET. Either way the final money moves across current accounts at the same Bank of Japan.
STRICTLY SPEAKING
Strictly speaking, the Zengin System runs many clearing cycles across the day and nets far more than one payment, and BOJ-NET's real operation depends on intraday liquidity management, payment queues, and operating-hour cut-offs not shown here. The single-cycle, single-payment view is a teaching simplification. The durable point is the architecture: a retail net rail and a large-value gross rail, split at JPY 100 million, both finalizing across the Bank of Japan's books.
FOR NOW, REMEMBER
- BOJ-NET is the Bank of Japan's real-time gross settlement (RTGS) system for the yen: large-value payments settle individually and immediately across current accounts at the Bank of Japan.
- The Zengin System, operated by Zengin-Net, is the interbank clearing network for domestic retail credit transfers; positions are netted and then settled across accounts at the Bank of Japan.
- Payments of JPY 100 million or more are diverted to RTGS in BOJ-NET rather than riding the retail net cycle.
- Both rails finalize across the same central-bank accounts — the difference is gross-and-immediate versus netted-and-deferred.
TRY IT YOURSELF
Bank Alfa needs to send Nordbank a single domestic yen payment of JPY 300,000,000 and wants it final as soon as possible. Which routing fits Japan's arrangement, and why?
Japan's split at JPY 100 million is one country's answer to a question every payment system faces: when should money settle one-by-one in real time, and when is it safe to net and defer? That trade-off between RTGS and deferred net settlement is the next thing worth getting straight.
KEEP GOINGKey takeaways / 03
Three things to remember
- 01
Identify who instructs, processes, clears, settles, and ultimately receives the funds.
- 02
Keep the exchange of payment information separate from the movement of money.
- 03
Trace where validation, accounting, charges, and exceptions enter the journey.
Operational sequence / 06
Follow the message and decision path
This compact sequence is a learning model. Exact routing and rulebook behavior can vary by scheme, participant, and implementation.
Read the steps as text
- 01MessageBank Alfa submits the BOJ-NET transferBank Alfa (sending bank) → BOJ-NET Funds Transfer System · BOJ-NET funds transfer
Bank Alfa sends a real-time gross settlement (RTGS) funds-transfer message for a high-value yen obligation to Nordbank. This is an instruction — the money has not moved yet.
- 02ProcessingBOJ-NET checks the current-account balanceBOJ-NET Funds Transfer System
BOJ-NET checks that Bank Alfa's current account at the Bank of Japan holds enough to cover the payment, because an RTGS system settles each transfer in full or not at all.
- 03SettlementThe Bank of Japan settles the payment in real timeBank Alfa (sending bank) → Nordbank (receiving bank)
The Bank of Japan debits Bank Alfa's current account and credits Nordbank's, individually and immediately in central-bank money. Large-value payments of JPY 100 million or more settle this way.
- DR Bank Alfa's current account at the Bank of Japan — JPY 300,000,000
- CR Nordbank's current account at the Bank of Japan — JPY 300,000,000
- 04MessageNordbank is told the payment has settledBOJ-NET Funds Transfer System → Nordbank (receiving bank)
BOJ-NET confirms to Nordbank that the funds are on its current account at the Bank of Japan and the settlement is final, with the details of the payment.
- 05PostingNordbank books the fundsNordbank (receiving bank)
Because the interbank leg has already settled with finality across the Bank of Japan's books, Nordbank can record the credit on its own ledger without waiting for a netting cycle.
- CR Beneficiary's account at Nordbank — JPY 300,000,000
Read the steps as text
- 01MessageRiya instructs the transferRiya (payer) → Bank Alfa (sending bank)
Riya asks Bank Alfa to pay Arjun by a domestic credit transfer. The instruction is a request to move money; on its own it carries no funds.
- 02PostingBank Alfa debits Riya's accountBank Alfa (sending bank)
Once Bank Alfa accepts the instruction it books the debit. Riya's money has left her account, but no money has yet moved between the banks.
- DR Riya's current account at Bank Alfa — JPY 50,000
- 03MessageBank Alfa sends the transfer through the Zengin SystemBank Alfa (sending bank) → Zengin System (Zengin-Net)
Bank Alfa submits the transfer to the Zengin System, the interbank clearing network run by Zengin-Net, which routes the details on to the receiving bank.
- 04PostingNordbank makes the funds available to ArjunNordbank (receiving bank)
Having received the routed transfer, Nordbank credits Arjun so he can use the money, trusting that the interbank leg will settle later that day.
- CR Arjun's current account at Nordbank — JPY 50,000
- 05Clearing obligationThe Zengin Center calculates each bank's net positionZengin System (Zengin-Net)
The Zengin Center adds up all the day's transfers and works out one net amount each participant owes or is owed — these are obligations, not yet money.
Netting produces who-owes-whom. The banks do not have their money yet — that only happens at settlement across their Bank of Japan accounts.
- 06SettlementNet positions settle across accounts at the Bank of JapanBank Alfa (sending bank) → Nordbank (receiving bank)
The net positions settle across the banks' current accounts at the Bank of Japan, which finalizes settlement. Only now has money moved between Bank Alfa and Nordbank.
This retail transfer is well under JPY 100 million, so it settles on a deferred net basis. A transfer of JPY 100 million or more would instead settle one-by-one in real time (RTGS) in BOJ-NET.
- DR Bank Alfa current account at the Bank of Japan — JPY 50,000
- CR Nordbank current account at the Bank of Japan — JPY 50,000
Evidence & review / 07
Evidence & review
BOJ-NET and the Zengin System, Japan (Bank of Japan and the Japanese Banks' Payment Clearing Network); the RTGS-plus-retail-net-clearing split generalises to other markets.
What this brief simplifies: The Zengin Center's exact netting cycles and the RTGS-diversion threshold handling are summarised; ledger views show two entries only.
Sources for this brief3
- Official requirement
BOJ-NET Funds Transfer System ↗ — Bank of Japan · BOJ-NET Funds Transfer System: RTGS for yen; large-value payments settle gross
BOJ-NET is the RTGS core for the yen; retail net positions from the Zengin System settle across BOJ accounts.
- Official requirement
Zengin System ↗ — Japanese Banks Payment Clearing Network (Zengin-Net) · Zengin System: retail credit-transfer clearing, net settlement at the Bank of Japan; >= JPY 100m to BOJ-NET RTGS
Zengin clears retail credit transfers and nets positions settled at the Bank of Japan; large-value items are diverted to RTGS in BOJ-NET.
- Simplified educational illustration
Payments Signal editorial teaching models — Payments Signal
Used wherever diagrams, scenarios, figures, or example values are didactic constructions rather than sourced facts; every such use carries a simplifications disclosure. All people, companies, banks, and list entries in examples are fictional.