> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# The building blocks

> The five core nouns of core banking (Organization, Ledger, Asset, Account, and Balance), each in one sentence, in the order they depend on each other.

Walk into a library and the structure is obvious before anyone explains it. There is the library itself, the catalog that organizes everything, and the shelves. There is also what sits on each shelf right now, and the *kind* of thing a shelf holds. A core banking system has five pieces that line up the same way.

You only need to see how each one rests on the one before it.

## They stack in order

***

Each block depends on the one above it: a shelf sits in a library, a balance sits in an account. Here they are, top to bottom.

* **Organization**: your company, the outer boundary of everything you run. The *library building itself*. All your records live inside it and belong to it.
* **Ledger**: one self-contained book of records. The *catalog*. You can keep more than one, say one per business line or per region. Each ledger keeps its own independent, balanced set of books.
* **Asset**: the *kind* of value you track, such as a currency like USD, loyalty points, or anything countable. The *category of thing on a shelf*. The system tracks the unit separately from the amount, so it knows that 100 of one thing isn't 100 of another.
* **Account**: a container tied to one asset. A non-external account can have one or more keyed balance records. An external account has exactly one `default` balance. A *single shelf*. Every movement of money has accounts on both sides.
* **Balance**: one keyed record of the amount an account holds, including available and held amounts. Each balance record has its own sending and receiving settings. What sits *on the shelf at this moment*.

<Note>
  An **Organization** can hold many **Ledgers**. A **Ledger** holds many **Accounts**. An **Account** always has one **Asset** and can carry one or more keyed **Balance** records. Read top to bottom, each block is the home of the next.
</Note>

```mermaid mermaid theme={null}
flowchart TB
  O["Organization<br/>your company"]
  L["Ledger<br/>one book of records"]
  Acc["Account<br/>holds value, sends & receives"]
  Bal["Balance<br/>the amount held right now"]
  As["Asset<br/>the kind of value"]
  O --> L
  L --> Acc
  Acc --> Bal
  As -.-|"defines the unit"| Acc
  classDef box fill:#e8f0fe,stroke:#4285f4,color:#333;
  classDef bal fill:#fff8e1,stroke:#f4b400,color:#333;
  class O,L,Acc,As box;
  class Bal bal;
```

## A balance is a result, not a setting

***

A **balance** is the **result** of every movement into and out of the account, added up. You do not type it in or adjust it by hand. Money arrives, money leaves, and the balance is where that leaves you.

This is why the books stay trustworthy: you cannot edit a balance directly. Recorded movements with two sides each *move it into the shape it has*.

<Tip>
  A balance isn't always one single number you can spend. Part of it can be **available** (yours to use now) while part is **held**, set aside for a movement that hasn't finished.
</Tip>

## Next steps

***

<Note>
  **See it in Lerian**

  See the building blocks in practice: [Core entities](/en/products/midaz/core-entities), [Ledgers](/en/products/midaz/ledgers), [Accounts](/en/products/midaz/accounts), [Balances](/en/products/midaz/balances), and [Assets](/en/products/midaz/assets).
</Note>