U need to star with long sword because u need the bilgewater cutlass really fast to won your lane. If u follow the build as instructioned u will see that u can EASIYL own the enemy adc! u will have problems till lvl 4 but at lvl 4 u skilled your E a second time and can give really hard dmg at early. In the mid game u ll recognize that u can catchup with EVERYONE and EVERYTHING because of the ghost the flash the R and your Blade of the ruined king. Well in late u can EASILY 2 hit the enemy ADC and EASILY do tripples and quatras. U will have only 1 problem: STUNS. the weaknes of every ADC but adc hav the advantege of range... u dont u need to come close. But dont worry if u got stuned dont forgett to use your blade of the runed king INSTANTLY after becoming free and than go hitting with everything u have. Well if your team is there aswell you can just Q and the need to fix your mates for a moment and than its your chance to give incredibel DAMAGE! Well as i said u can own everything... BUT malz and leona are both good counters because of there extreme cc skills and the so long wearing stun! Beware of them and dont enter in anykind of teamfight with your Q: wait till the enemy is trieng to fix you and than use it to make yourself unfixable ^^! trust me MASTER YI AD is REALLY raping about everything!