How to find which masterchain block from workchain block

Hi everyone.
Following the shards docs, 1 block in master chain can be sharded into multiple blocks in work chain. But I see a block in work chain but can not find which master chain block it belong to?

For the master block in tonviewer, I look up for master block 20834331 but I do not see the workchain block 22357910 in this master block?