This build for tanking as Cho alows you to be a threat in team fights without giving up tanking power like most AP/Tank cho builds do. That being said you will NOT be taking out the enemy solo you are the tank not the ganker.

you will be taking runes of vitality because this build does not take many hp items and the runes of vitality help make up for that fact you can really take any defensive runes you like but i find vitality works well for me personaly

masteries are pretty much build for as much defense as you can to help you complete your tank roll

starting with Boots and three hp potions is pretty standard.

you want to take heart of gold on your first recall to give you more hp and for the added gold bonus which will help you complete your early build faster.

mercury treads are taken for the great anti CC ability they give as well as some magic resist

Wardens mail and glacial shroud are teken next because together they give you an added 95 armor 20hp regen 425 mana and reduced cooldowns by 15% alowwing you to stack feast more quickly if that wasnt enough wardens mail will slow the attack speed of those anoying AD carries who love to stack attackspeed you know the ones.

by this point the enemy has also started building thier champions so we need to get som offensive ability thats why we take abyssal sceptor for the AP and majic resis it also lowers enemy magic resist helping you and any of your magic using team to take them out quicker

randuins omen gives you more versitility it adds armor and cooldown reduction and gives you a pretty crippling aoe slow on activation which helps mop up team fights or helps your team pull out of a nasty spot

frozen heart for more armor and reducing enemy atack speed even more

force of nature alowws you to stay out with your team almost indefinitly with the hp regen and gives more magic resist as well

i rarely get this far to complete my build by this point you have won or lost but if you do get to complete your build you take rod of ages it will make you more lethal and gives you hp and mana cant really go wrong here

**note if your enemy is building AP more than AD build force of nature before frozen heart

early game just go bot and help your lane mate farm and harrass the enemy so they cant farm now this build doesnt build mana till later so you have to know how to manage your abilities rupture spam will exaust your mana make them count.
while playing cho as a tank you should be the initiator of all team fights and you should be the last to leave them harrass and silence your enemys as much as you can to help your team
dont forget your active aoe slow randuins omen it can make or break a team fight used properly
other than that play smart dont feed the enemy and work your team to victory