# How to Create Your Own Subchain

Before you create your own subchain, make sure you have done things below:

* sync and run pchain
* have at least one address and one consensus key
* have at least 200k PI on your address

Here is an example of priv\_validator.json which stores your address and consensus keys:

```
{
"address": "4CACBCBF218679DCC9574A90A2061BCA4A8D8B6C",
"consensus_priv_key": [
        4,
        "D8AF52E355CD070ED3401800CBC920B6E94F3C49B42808C3049BF7BDB1FA3B19"
],
"consensus_pub_key": [
        4,
        "085586D41F70435700850E19B7DE54B3E793C5EC4C6EC502D19030EF4F2122823E5A765E56CBA7B4C57E50561F77B022313C39895CA303F3C95D7B7282412F334778B95ACE046A79AEA4DB148334527250C8895AC5DB80459BF5D367236B59AF2DB5C0254E30A6D8CD1FA10AB8A5D872F5EBD312D3160D3E4DD496973BDC75E0"
]
}
```

{% hint style="warning" %}
Do not create a different subchain with the same address. You can find this priv\_validator.json file in the datadir/.pchain/pchain directory.
{% endhint %}

### Create Subchain

Suppose you are going to create a subchain with a chain id as “mychain”, and you want your subchain to start with one validator with a minimum of 100k deposit PI.

You can create subchain by [RPC chain\_createChildChain](https://github.com/pchain-org/pchain/wiki/JSON-RPC#chain_createchildchain).

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_createChildChain","params":["from","chainId", "minValidators", "minDepositAmount", "startBlock","endBlock"],"id":1}' localhost:6969/pchain
```

In this case, the command should be:

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_createChildChain","params":["0x4CACBCBF218679DCC9574A90A2061BCA4A8D8B6C","mychain", "0x1", "0x152D02C7E14AF6800000", "0x32","0x7D0"],"id":1}' localhost:6969/pchain
```

You can set parameter `startBlock` very small and set parameter `endBlock` very big to make sure you won't miss it. Once successful, your account will deposit 100k PI on the subchain. If you didn't finish the second step, the deposit will be back to your account once the main chain reaches the `endBlock` height.

{% hint style="info" %}
Note: This is only the first step, you need to finish the second step, or the chain won't start.
{% endhint %}

### Join Subchain

Before you join the subchain, you need to generate a signature signed by your consensus private key. You can generate it by [RPC chain\_signAddress](https://github.com/pchain-org/pchain/wiki/JSON-RPC#chain_signAddress).

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_signAddress","params":["address", "consensus private key"],"id":1}' localhost:6969/pchain
```

In this case, the command should be:

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_signAddress","params":["0x4CACBCBF218679DCC9574A90A2061BCA4A8D8B6C", "0xD8AF52E355CD070ED3401800CBC920B6E94F3C49B42808C3049BF7BDB1FA3B19"],"id":1}' localhost:6969/pchain
//"0x1214608bcdf2e464b2d37d19b1b671482253e275d33079264045253fbb18689385ac0d5b4128d0c593211588deafd9ea2507b4858bdd42aaef3999045c0407ae"
```

Remember the return hash.

Now you need to join the subchain, in this example, you need at least one validator with at least 100k deposit PI to let your subchain start. You can join the subchain by [RPC chain\_joinChildChain](https://github.com/pchain-org/pchain/wiki/JSON-RPC#chain_joinchildchain).

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_joinChildChain
.","params":["from","pubkey", "chainId", "depositAmount", "signature"],"id":1}' localhost:6969/pchain
```

In this case, the command should be:

```
curl -X POST -H "Content-Type:application/json" --data '{"jsonrpc":"2.0","method":"chain_joinChildChain","params":["0x4CACBCBF218679DCC9574A90A2061BCA4A8D8B6C","085586D41F70435700850E19B7DE54B3E793C5EC4C6EC502D19030EF4F2122823E5A765E56CBA7B4C57E50561F77B022313C39895CA303F3C95D7B7282412F334778B95ACE046A79AEA4DB148334527250C8895AC5DB80459BF5D367236B59AF2DB5C0254E30A6D8CD1FA10AB8A5D872F5EBD312D3160D3E4DD496973BDC75E0", "mychain", "0x152D02C7E14AF6800000", "0x1214608bcdf2e464b2d37d19b1b671482253e275d33079264045253fbb18689385ac0d5b4128d0c593211588deafd9ea2507b4858bdd42aaef3999045c0407ae"],"id":1}' localhost:6969/pchain
```

After this transaction succeeds and the main chain reaches `startBlock` height, your chain will start.

### Check

Once your chain started, you will find a directory named with chain id under datadir/.pchain/, in this case, it should be `datadir/.pchain/mychain`, you can attach to its console by command:

```
./bin/pchain attach .pchain/mychain/pchain.ipc
```