From 'Nine in the Fifth Place' to 'no blame.' Sub-commentary: Purslane is a soft and brittle herb. The meaning of Breakthrough is to use the firm to decide the yielding, the noble person purging the petty person.
The fifth line dwells in the honored position, being the master of Breakthrough; deciding Six at the Top in person, the decision is exceedingly easy, just like snapping purslane; hence 'a resolute breakthrough like purslane.'
However, using supreme honor to confront the lowest base, even if it overcomes, it is not worthy of esteem. Only because of acting in the middle way does it barely avoid blame; hence 'acting in the middle way brings no blame.' Note: 'Purslane is a soft and brittle herb.'
Sub-commentary: Zi Xia's commentary says: 'Purslane has woody roots and herbaceous stems, firm below and soft above.' Ma Rong, Zheng Xuan, and Wang Su all say: 'Purslane, another name is shanglu (pokeweed),' taking purslane as one single plant.
Huang Yu says: 'Xian is human amaranth; lu is pokeweed,' taking them as two. Note: the commentary directly says 'a soft and brittle herb,' which also treats them as one, agreeing with Zi Xia and others.