Kenter shackles are used for this job.
See http://www.anchormarinehouston.com/Kenter.html
"Courtney Thomas" wrote in message
news
With objectives of:

1-proper strength
2-avoiding interference with the windlass
3-segment disconnect when desired & avoiding compromising #s 1 & 2

what is the recommended technique for durably connecting two lengths of
same size anchor chain ?

Thank you,

Courtney