# Etherscan Forked Blocks' Reorg-Depth is Incorrect?

I suddenly found there is an reorg happened today whose depth is 3 on Etherscan.io here. The uncle blocks is at height `9919331` and the hash is `0x3b1161a8bdf5107f1dc2092781798d143b5ae66b6604823630b57f5d9450e1cb`. However I further checked the structure of the blockchain history and found the structure is like this:

``````0xa0f0 => 0xc535 => 0x7ea3
\
0x3b11
``````

`0xa0f0`,`0xc535`,`0x7ea3` represent the blocks (first 16 bits of their hashes) in canonical chain, while `0x3b11` is the uncle block reported by Etherscan with reorg-depth 3. The hash of `0x3b11` is included as uncles in the block `0x7ea3`.

I am very confused why Etherscan reports this uncle blocks as reorg-depth 3. It seem this reorg only discard one block (i.e. `0x3b11`). Is this a problem in Etherscan? or are there some uncle blocks overlooked by me?

Let's suppose a node has this state

``````A -> B -> C -> D
``````

New blocks arrive and the situation becomes:

``````A -> B' -> C' -> D' -> E -> F
|
B
``````

(Where B is included as an uncle block in C'.)

Since 3 blocks were replaced the reorg has depth 3

The inclusion of B as an uncle in C' doesn't reflect the depth of the reorg.

For example it might have been included further down the chain in D', E or F.

To be included as uncle the block's parent has to be in the main chain. Since B is no longer part of the main chain its children C and D cannot be included as uncle blocks.

• Thanks for answer. Why uncle C and D are not included in any blocks? Apr 23, 2020 at 13:24
• @Aaron To be an uncle block its parent should be part of the main chain. Since B is not part of the main chain its children C and D cannot be uncles.
– Ismael
Apr 23, 2020 at 14:06
• @lsmael. I see. Is it possible to get block C and block D (the hash and transactions in them)? Apr 23, 2020 at 14:18
• @Aaron It might be possible that some nodes still have them when the fork happened. But after sometime they will be lost because they are not part of the main chain.
– Ismael
Apr 23, 2020 at 14:31
• @lsmael, in case when they are still stored on some nodes, where can I get the hash of block C and D to query them on the node? Apr 23, 2020 at 14:57