Sun Tzu is saying that if a military force is fighting on ground that is highly contested or disputed, and possession of this ground offers a great advantage, it is important to secure and hold onto that ground. In order to do this, Sun Tzu suggests bringing in additional troops or supplies to reinforce and support the main force that is already on the contentious ground. In other words, Sun Tzu is recommending that the rear (or the supporting elements of the military force) be hurried up to join the main force on the contentious ground, in order to strengthen the defense and maintain control over this strategically important terrain.
On contentious ground, a business should quickly focus its resources in this market.
In business, contentious ground refers to a market in which the business which has a dominate position gains a great advantage. Since a business can gain a significant advantage by controlling this market, it should quickly focus its resources on further securing and maintaining the dominant position.
To do this, the business might need to bring in additional resources such as capital, personnel, or technology, in order to reinforce and support its efforts in this market. This might involve investing in marketing and advertising to increase brand awareness, developing new products or services to meet the needs of customers in the market, or building partnerships and alliances to expand the company’s reach and influence. Essentially, the business would be “hurrying up its rear” by marshalling its resources and focusing them on the contentious ground, in order to secure and maintain a strong position in the market.