Retrieve the content of a json file using shell script .Without jq /json

I need to get the read contents of this json file
{
"instance": {
"id": "i-061a20e8c5",
"taglist" : [
{"Key": "acp-ims-backup","Value": "sqldb"} ,
{"Key": "created by","Value": "Historia"}
],
"backup_config_clientname": "CAJ-i-061a20e8c"
}
}

I want the value of "backup_config_clientname"
I can assign it to a variable and print it.
using awk or sed .

Thanks in advance