The “indirect approach” and “centre of gravity” are two concepts central to modern strategic thought. Both have a long tradition. However, there continues to be debate over how these concepts should be interpreted and applied. The indirect approach advocates against attacking the adversary’s strength head-on while the centre of gravity refers to the most critical point of the adversary’s system. Logically extrapolating forward, there is a synergistic outcome when both concepts are considered in conjunction. This article argues that the indirect approach is most potent when directed against a centre of gravity. It does so by first unpacking what each concept means using the Gallipoli operation (1915-1916) as a point of reference. The article then examines the historical example of Besieging Wei to Rescue Zhao (围魏救赵) to illustrate how the indirect approach combines with the centre of gravity to achieve optimal results. Such was the success of the campaign which saved Zhao (354-353 BC) that it has since been immortalised in the form of a famous Chinese proverb, and provides the basis for one of the stratagems recorded in the Chinese military classic known as the Thirty-Six Stratagems (三十六计).[1]
The Indirect Approach
The indirect approach in war is not new. It was, however, more recently popularised by B. H. Liddell Hart in his post-war strategic writings, the most well-known being now titled Strategy.[2] Having witnessed the carnage wrought amidst the stalemate in the trenches during the First World War, Liddell Hart advocated against the futility of direct confrontation. He asserts the commanders of the day had misinterpreted Clausewitzian doctrine and by extension became obsessed with the idea of directly seeking out the adversary's main force and destroying it in decisive battle.[3] While there have been criticisms that Liddell Hart’s conclusion was too sweeping, oversimplifying the theories put forth in Clausewitz’s writings, there is some validity to Liddell Hart’s assertion that using the direct approach against the adversary’s strength was too costly a military stratagem.[4] Unless the adversary’s strength was far inferior, at the military-strategic level destroying an adversary’s main force would require a force of at least equivalent strength but likely more, resulting in costly and potentially long-drawn battles of attrition.[5]
The problem with Liddell Hart’s concept was that while it was logical in a theoretical sense, it was far more complicated in application.
Instead, Liddell Hart proposed the indirect approach as an alternative. The basic principle behind this approach was that the adversary’s strength should be circumvented in favour of indirect blows against his more vulnerable points. By choosing and exploiting the line or course of least resistance, the adversary’s equilibrium could be offset, causing dislocation.[6] By also widening the range of objectives away from one single focal point, one was able to hedge the chances of success, allowing for an advantage to be accrued incrementally.[7] To be sure, Liddell Hart did not rule out the possibility of direct confrontation, but the point was only to attempt this after one had positively shifted the balance of force in his favour via the indirect approach.[8]
“The Landing at Anzac, 1915” by Charles Dixon (via Wikimedia Commons)
The problem with Liddell Hart’s concept was that while it was logical in a theoretical sense, it was far more complicated in application. While Liddell Hart argued that direct confrontation would inevitably lead to futile costly exchanges, an ill-conceived application of the indirect approach could potentially lead to the frittering away of resources chasing vague outcomes.[9] An example of this was the Gallipoli operation that took place during the First World War. As the historian Robin Prior notes in his analysis of the strategy behind the operation, the Entente Powers’ plan to break the stalemate on the Western Front by forcing a breakthrough via the Ottoman Empire, one of the weaker members of the Central Powers, would unlikely have any significant impact on the course of the war due to the peripheral nature of that theatre.[10] Even if the operation had succeeded, it would have likely been a distraction for the Germans. Yet, through a combination of unrealistic planning and poor execution, valuable allied manpower and material were wasted in the Dardanelles. Something about the indirect approach was lacking, and it is here that the application of centre of gravity is complementary.
Understanding the Centre of Gravity
There is no exact consensus over how to define the centre of gravity, with different schools of thought emerging that revolve around the degree of its accepted utility in planning.[11] The centre of gravity as a concept has taken on various meanings to serve different purposes, but Clausewitz’s original conceptualisation is still the most influential. Defined as the “hub of all power and movement, on which everything depends,” the centre of gravity could be interpreted as many things.[12] At the tactical or operational level, it could be defined as the strongest concentration of the adversary’s military strength, or his most critical operational asset.[13] Because the operational environment evolves dynamically, the centre of gravity can shift as the campaign unfolds.
At the military-strategic level, however, the consideration of the centre of gravity expands beyond a particular locality, facilitated further by how technology redefines conceptions of space and mobility.[14] Here, Antulio J. Echevarria’s suggestion that the centre of gravity is the focal point toward which all parts of the adversary’s system or structure gravitates, holding it together, is helpful.[15] In this definition, the centre of gravity is neither a strength nor weakness, but rather a strategic intersection upon which the ability of the adversary’s system to function hinges. Applying this definition to the Gallipoli operation discussed earlier, it becomes apparent that the failure in strategy laid in the incorrect identification of the centre of gravity. Given that it was Germany’s war production and manpower and not the Ottomans’ that was central to the overall war effort, no quick resolution to the war could have been brought about that did not include the collapse of German military power.[16] The indirect approach here thus failed because it lacked an effective focal point for its energies.
A logical outgrowth from an understanding of the indirect approach and the centre of gravity would then be to explore how both could be considered in conjunction with each other to produce outsized outcomes.
Combining the Indirect Approach with the Centre of Gravity
A logical outgrowth from an understanding of the indirect approach and the centre of gravity would then be to explore how both could be considered in conjunction with each other to produce outsized outcomes. If the indirect approach is a means to achieve an objective, then there needs to be proper identification of the objective to achieve maximal effect. In short, applying the indirect approach against the adversary’s centre of gravity would potentially cause his system to unravel while incurring minimal losses. While this might, at first glance, seem to contradict Liddell Hart’s tenet of diversifying the range of objectives, it is in actuality a reminder that all efforts must ultimately be contrived with a clear view of what the endpoint is in mind. This is the basic tenet behind the proverb Besieging Wei to Rescue Zhao.
Besieging Wei to Rescue Zhao (Chinese Time School)
The origins of the proverb lie in a military campaign fought between the states of Zhao (赵) and Wei (魏) during China’s Warring States period, approximately 475 to 221 BC, which culminated in the siege of the state of Zhao’s capital by the army of Wei. Faced with this desperate situation, the Zhao turned to the neighbouring state of Qi (齐) for aid. However, instead of rushing to attack the besiegers head-on, the Qi army responded to Zhao’s request by launching a military feint against the Wei capital. As elucidated by Sun Bin (孙膑), the Qi army’s military strategist, “to loosen an entangled knot, a clenched fist will not suffice; to settle a quarrel, rushing into the midst of the fight is not helpful” (夫解杂乱纷纠者不控卷, 救斗者不搏撠).[17] Arguing that the defences of the Wei capital were weak with the Wei army’s elite tied down in Zhao, he instead advocated attacking it to force the Wei army to rush back reinforcements, indirectly relieving the siege of Zhao.[18] Accepting Sun’s advice, the Qi commander ordered his army to move on the Wei capital and the Wei commander responded just as expected, rushing his crack cavalry back from Zhao where it was ambushed en route and destroyed by the waiting Qi army in the Battle of Guiling (桂陵之战).
Analysing the campaign through the concepts discussed earlier, it can be seen that the Qi’s indirect approach succeeded because the focus of its thrust was directed at the adversary’s centre of gravity –– the Wei capital –– which was its hub of political power. If Qi had gone straight for Wei’s main army, it might still have succeeded in relieving the siege, but would have done so at greater material cost. If it had gone for other peripheral vulnerabilities instead of the Wei capital, the strikes might not have been significant enough to divert the Wei army from its course of action. Instead, because the Qi correctly struck at Wei’s centre of gravity using the indirect approach, they were able to effectively achieve the broader objective of relieving the siege of Zhao. More importantly, the Qi were able to wrest the initiative away from Wei and gain control of the entire situation, dictating how the Wei should move and respond.
Although the Wei capital’s strategic significance was not explicitly highlighted in the record, its value as a critical centre of gravity can be reasonably assumed given that ultimate control of the state’s military power was vested in the king, who resided in the capital where he administered the affairs of the state. Clausewitz likewise argued that capital cities could be considered as possible centres of gravity if they were the country’s centre of administration, social, professional, and political activity.[19] The choice to attack the capital rather than other lesser targets should also be seen as significant in itself, given Sun Tzu’s (孙子) earlier admonishment to only lay siege to cities as a last resort.[20]
Conclusion
Incorporating the centre of gravity with the indirect approach makes one’s actions more potent, providing an effective focal point that if successfully hit promises high yields for minimal costs. While like any other stratagem it will not always be possible to find the opportunity for both to be applied in conjunction with each other, perhaps because one lacks the options for manoeuvre or the centre of gravity is too well guarded, as was the case with Germany in World War I, the yield is exponentially increased when a convergence exists.
As shown in this case, the indirect approach and the centre of gravity are rich strategic concepts that produce outsized outcomes when considered together. This is illustrated in the strategic considerations that underpin the case of Besieging Wei to Rescue Zhao. Specifically, a closer analysis of the campaign shows that the indirect approach is most potent when directed against a centre of gravity. Although this might seem an oversimplification of the complex nature of military operations, this maxim remains useful as a tool to guide planning. On the converse, a failure to appreciate how the concepts work with each other can result in the wasteful allocation of military resources, such as that witnessed during the Gallipoli operation. Given the complementary nature of both concepts, seeking the convergence between both is not only desirable but imperative.
Ian Li is a senior analyst with the Military Studies Programme at the S. Rajaratnam School of International Studies, Singapore.
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Header Image: The 36 Strategems (Wikimedia Commons)
Notes:
[1] Stefan H. Verstappen, The Thirty-Six Strategies of Ancient China (San Francisco: China Books & Periodicals, Inc., 1999).
[2] B. H. Liddell Hart, Strategy, Second Revised ed. (New York: Meridian, 1991).
[3] Ibid., 319.
[4] Christopher Bassford, Clausewitz in English: The Reception of Clausewitz in Britain and America 1815-1945 (New York & Oxford: Oxford University Press, 1994), 128-135.
[5] Joseph A. Gattuso Jr., “Warfare Theory,” Naval War College Review 49, No. 4 (Autumn 1996): 114-117.
[6] Liddell Hart, Strategy, 334-337.
[7] Ibid.
[8] Ibid.
[9] Joshua Schwartz, “When Trying to Surprise Your Opponents Backfires: Exposing the Weaknesses of the Indirect Approach,” Cornell International Affairs Review 10, No. 2 (2017): 105-128, https://journals.library.cornell.edu/index.php/ciar/article/view/493.
[10] Robin Prior, “The Strategy Behind Gallipoli: Strategic decision-making in the Dardanelles and Gallipoli,” Australian Strategic Policy Institute (APSI) Strategic Insights No. 15 (2005): 1-9.
[11] Dale C. Eikmeier, “The Center of Gravity: Still Relevant After All These Years?,” Military Review: The Professional Journal of the U.S. Army (May 2017): 2, https://www.armyupress.army.mil/Portals/7/Army-Press-Online-Journal/documents/Eikmeier-v2.pdf.
[12] Carl Von Clausewitz, On War, eds. and trans. Michael Howard and Peter Paret (Princeton: Princeton University Press, 1989), 595-596.
[13] Lawrence L. Izzo, “The Center of Gravity is not an Achilles Heel,” Military Review 68, No. 1 (January 1998): 72-77.
[14] Wolfgang Schivelbusch, The Railway Journey: The Industrialization of Time and Space in the Nineteenth Century (California: University of California Press), 33-44. While Schivelbusch’s study focuses on the impact of the railway in the 19th century, it is worth considering how modern developments such as those in the digital domain redefine space and mobility in the military context.
[15] Antulio J. Echevarria II, "Clausewitz’s Center of Gravity: It’s Not What We Thought," Naval War College Review 56, No. 1, Article 6 (2003): 112-115, https://digital-commons.usnwc.edu/nwc-review/vol56/iss1/6.
[16] Robin Prior, “Gallipoli as a combined and joint operation,” in Naval Power and Expeditionary Warfare: Peripheral campaigns and new theatres of naval warfare, eds. Bruce A. Elleman and S.C.M. Paine (London & New York: Routledge, 2011), 54-56.
[17] Sima Qian (司马迁), A Complete Translation of the Twenty-four Official Dynastic Histories: Records of the Grand Historian (二十四史全译 : 史记), eds. Xu Jialu (许嘉璐) and Ang Pingqiu (安平秋) (Shanghai: 汉语大词典出版社, 2004), 900-901.
[18] Ibid.
[19] Clausewitz, On War, 595-597.
[20] Sun Tzu, The Art of War, trans. Peter Harris (New York, London & Toronto: Everyman’s Library, 2018), 53-54.