</div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Insomniac @ Jan 20 2004, 10:04 AM)</td></tr><tr><td id='QUOTE'> skill level doesnt make a difference to whether or not the person lives. they&#39;ll always die, its the way the jutsu is preformed.
also it seems that you need a great deal of strength to be able to pull the souls out of their bodies (as we see the 3rd faulters after pulling out the 1st and 2nds souls and only achieving Oro&#39;s arms after)

you have to sign the contract to even SEE the jutsu so that means if Orochimaru had never seen it before then i&#39;m sure Kakashi hasnt either

when the 4th sealed the Kyuubi on lookers would have not know what jutsu he used because they wouldnt be able to see it, also it wouldnt have been able to be copied either

if Orochimaru didnt know it and he was in the 3rds team then why would Kakashi know it?

simply put, we wont see that jutsu again because both of its users have died and they were the only ones we know of with contracts with the summon </td></tr></table><div class='postcolor'>
This is exactly my point.

Plus maybe its a move that only hogake can do so Tsunade must learn somehow.