The four inner offerings bodhisattvas occupy positions inside the vajra circle and relate to inward things of the body and mind. As emanations of Mahāvairocana 大日如來, this group is comprised of Vajralāsī 金剛嬉, Diamond Joy, situated in the SE, an offering to Akṣobhya 阿閦; Vajramālā 金剛鬘, Diamond Garland, situated in the SW, an offering to Ratnasaṃbhava 寶生; Vajragīta 金剛歌, Diamond Song, situated in the NW, an offering to Amitâbha 阿彌陀; Vajranṛta 金剛舞, Diamond Dance, situated in the NW, an offering to Amoghasiddhi 不空成就.

The four outer offerings bodhisattvas occupy positions outside the vajra circle, in the four corners of the outer layer, and relate to things outside the body and mind. As emanations of the dhyāni-buddhas, this group is comprised of Vajradhūpā 金剛香, Diamond Incense, situated in the SE, offered by Akṣobhya 阿閦; Vajrapuṣpā 金剛華, Diamond Flower, situated in the SW, offered by Ratnasaṃbhava 寶生; Vajralokā 金剛燈, Diamond Lamp, situated in the NW, offered by Amitâbha 阿彌陀; Vajragandhā 金剛塗香, Diamond Perfume, situated in the NE, offered by Amoghasiddhi 不空成就. Abbreviated as 八供. 〔金剛峰樓閣一切瑜伽瑜祇經 T 867.18.268a18; 大教王經, 佛頂脩瑜伽法軌儀〕

References:

Snodgrass, Adrian. 1988. The Matrix and Diamond World Mandalas in Shingon Buddhism. New Delhi:  Aditya Prakashan.

Somekawa, Eisuke, and Michihiko Komine. 1993. Mandara zuten曼荼羅図典 . Tokyo:  Daihōrinkaku.