A lot of people have asked me how to do the Yuffie subquest in Utai, so here goes. Note this can only be done on the 1st or 2nd disc.

As soon as you get the Tiny Bronco get right off at the beach on your left. From here head up North through the mountains. Once you've gone far enough Yuffie will come out( you must have her in your party) and steal your materia and leave you with two shinra guards. Once you've killed them continue to head through the mountains. Once you've crossed all the bridges and crossed the last of the mountains you'll find Utai. Enter and head in the bar were you'll meet the Turks. Then go into the materia shop to the North of the bar and open the treasure chest. You'll get the MP absorb materia, to bad Yuffie will come by and steal it. Now continue to the West and enter the house on the left on the new screen. Go talk to the man thats lying down several times. You'll soon see Yuffie pop down then run away. Head back out to the main part of Utai. You'll have to enter the house on your left when you first came into Utai( the one with the old man and little boy). Pull back the curtain and watch once again as Yuffie escapes. Head back towards the bar and you'll see a jar thats moving. Go up to it and punch it three times and out will pop Yuffie. She'll lead you into your house, were you'll once again be tricked. Note it doesn't matter what lever you pull. Once again head back to Godo's house( the 1st house you went into) and go up to the cannon to the left of it. Press circle against it and a secret door will open below. Go in and you'll find none other than Don Cornero. Chase him out and after your battle with the Shinra forces head into the Da-Chao Mountains( God Bless You). Follow Reno then head South of the cave Rude goes into. Here you'll trap Don and he'll make you fight a boss. I did this on the first disc and the boss was rather hard. The easiest party to beat him with is Cloud, Aeris, and Vincent. Finally Yuffie will give you back your materia. If you head into the bottom part of her house with all the cats one will move reveling a stair case. Climb it and you'll find a HP Absorb Materia. Now you can finally continue your quest.