How did private estates weaken the central government during the Heian period?

During the Heian period, the rise of private, tax-exempt estates known as shōen significantly undermined the central government's authority by encroaching upon the public domain and eroding the state's economic foundation.12

These estates weakened the central administration in several key ways:

• Loss of Tax Revenue: As land was increasingly commended to powerful families—such as the Fujiwara family—or to religious institutions, it became exempt from taxation. This diverted vital public revenues away from the imperial government and into private coffers.13
• Administrative Independence: These estates became autonomous, effectively operating outside the control of the civil administrative system. This independence reduced the reach and substance of state governance.12
• Rise of Local Military Power: The growth of these estates contributed to the emergence of a local military class. As the central government failed to check the expansion of these private holdings, the landed gentry increasingly turned to provincial warrior families for protection. This shift in loyalty strengthened military clans, eventually leading to the decline of the court aristocracy's influence and the rise of the samurai class.123