大般涅槃經義記 1.120

1.120

自下第十，明諸大眾由土清淨徹見十方微塵數剎，於中初法、次喻、後合。文殊向前言「以佛力當見九方」，指此事耳。此見十方，何故言九？前者告時，已見東方，對此所見，故偏言九。

From here down is the tenth, explaining that due to the purity of the land, the assemblies clearly saw lands as numerous as the dust motes of the ten directions. Within this, there is first the dharma, next the metaphor, and finally the application. Mañjuśrī's earlier statement that "Through the Buddha's power you will see the nine directions" refers precisely to this matter. Here they see the ten directions; why does it say nine? Earlier, when he told them, they had already seen the eastern direction; relative to what was seen here, he specifically said nine.