Complex sentence: The faction was headed by Colonel Itagaki Seishiro (板垣 征四郎) and Lieutenant-Colonel Ishiwara Kanji (石原 莞爾), who were having trouble attracting Japanese settlers or investment into Manchuria.
Split into simpler sentences: The faction was headed by Colonel Itagaki Seishiro (板垣 征四郎) and Lieutenant-Colonel Ishiwara Kanji (石原 莞爾). They were having trouble attracting Japanese settlers or investment into Manchuria.