> Previous [proposal](https://kusama.polkassembly.io/proposal/66) fails because of wrong weight estimation, error fixed in this proposal.

The aim of this proposal is to open a bi-directional **HRMP** channel between **Statemine** and **Shiden**. Shiden’s parachain Id is **2007** and this is used in **HRMP** calls for channel opening.

Since previous call was unsuccessful due to incorrect max weight, we do not transfer funds for channel opening from Kusama treasury, only 1 KSM to cover the execution fees. Unused funds are returned back to the treasury.

### 1. Channel Init Open & Accept

Encoded call data for a batch call to

- accept channel opening from Shiden
- initiate channel opening with Shiden

`0x1800083c01d70700003c00d7070000e803000000900100`

This can be [decoded](https://polkadot.js.org/apps/#/extrinsics/decode) on **Kusama**.

### 2. XCM from Statemine to Kusama

Encoded call data to send XCM message from Statemine to Kusama which will execute the aforementioned batch call.

`0x1f000101000214000400000000070010a5d4e81300000000070010a5d4e800060003009435775c1800083c01d70700003c00d7070000e803000000900100140d010004000101006d6f646c70792f74727372790000000000000000000000000000000000000000`

This can be [decoded](https://polkadot.js.org/apps/#/extrinsics/decode) on **Statemine**.

Statemine will send a request to Kusama to open & accept channel opening as described in the 1st sub-chapter. Unused funds are refunded back to the treasury account.

### 3. XCM from Kusama to Statemine

The preimage hash for **Kusama**:

`0x66cb3ecc23fd2ef262f8f451e4f0e0dfcfd2e276b3438dc800522df4863659db`

Encoded call data:
`0x1800080402006d6f646c70792f747273727900000000000000000000000000000000000000000070617261e8030000000000000000000000000000000000000000000000000000070010a5d4e8630001000100a10f0204060203009435779d011f000101000214000400000000070010a5d4e81300000000070010a5d4e800060003009435775c1800083c01d70700003c00d7070000e803000000900100140d010004000101006d6f646c70792f74727372790000000000000000000000000000000000000000`

This can be [decoded](https://polkadot.js.org/apps/#/extrinsics/decode) on **Kusama** and hash can be verified.

Kusama will send a XCM to Statemine in order to initiate the procedure described in second sub-chapter.

Send a batch of dispatch calls.

May be called from any origin.

- `calls`: The calls to be dispatched from the same origin. The number of call must not
  exceed the constant: `batched_calls_limit` (available in constant metadata).

If origin is root then call are dispatch without checking origin filter. (This includes
bypassing `frame_system::Config::BaseCallFilter`).

# <weight>
- Complexity: O(C) where C is the number of calls to be batched.
# </weight>

This will return `Ok` in all circumstances. To determine the success of the batch, an
event is deposited. If a call failed and the batch was interrupted, then the
`BatchInterrupted` event is deposited, along with the number of successful calls made
and the error of the failed call. If all were successful, then the `BatchCompleted`
event is deposited.



1. Batch call to accept & open HRMP channel between Statemine and Shiden with Shiden's parachain ID 2007.
2. Statemine sends a XCM request to Kusama to execute call from part 1.
3. Kusama sends XCM to Statemine, containing the hash to verify the execution of part 2 and initiate channel opening.

#218 HRMP Channel Opening: Shiden <> Statemine

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