each individual hoplite carried his shield on his left arm, protecting not only himself but also the soldier to the left. this meant that the men at the extreme right of the phalanx were only half-protected. in battle, opposing phalanxes would try to exploit this weakness by attempting to overlap the enemy's right flank. it also meant that, in battle, a phalanx would tend to drift to the right (as hoplites sought to remain behind the shield of their neighbor). the most experienced hoplites were often placed on the right side of the phalanx to avoid these problems. some groups, such as the spartans at nemea, tried to use this phenomenon to their advantage. in this case, the phalanx would sacrifice its left side, which typically consisted of allied troops, in an effort to overtake the enemy from the flank. it is unlikely that this strategy worked very often, as it is not mentioned frequently in ancient greek literature.