In the year of 3681 BBY, the reestablished Sith Empire strategically obstructed the Rimma Trade Route, aiming to deplete the Galactic Republic's resources. This action marked one of the initial confrontations of the Great Galactic War, transpiring shortly after the Empire's return to the known galaxy. As part of the Sith Emperor's scheme to dominate the galaxy's Outer Rim Territories, the Rimma super-hyperroute was shut down, leading to additional Republic setbacks and internal political disorder. While Republic forces in the Outer Rim suffered from shortages of supplies and reinforcements—notably those within the contested Minos Cluster—military commanders initiated efforts to reclaim the Rimma Trade Route. Following the Republic Army's initial failed offensive, the blockade ceased in 3680 BBY, subsequent to a fleet belonging to the Republic Navy reorganizing in the Seswenna sector and commencing a second offensive. This assault successfully broke the Empire's grip on the route, enabling the Republic to transport war supplies and reinforcements to Outer Rim battlegrounds.
After existing in exile for over a millennium within the Unknown Regions of the galaxy, the ancient Sith Empire resurfaced in galactic awareness during 3681 BBY in a new and powerful iteration, determined to annihilate the Galactic Republic and the Jedi Order in a war that became known as the Great Galactic War. The Sith's commander, solely identified as the Sith Emperor, guided his forces in a campaign aimed at securing the Outer Rim Territories through a rapid and merciless advance. Following highly successful operations within the Tingel Arm region and the recapture of the Sith's ancestral homeworld of Korriban, the Empire expanded its advantage and broadened its offensive. Imperial forces invaded the Minos Cluster and initiated a massacre on the Republic shipyard world of Sluis Van. Simultaneously, the Imperial Armada focused on the highly valuable Rimma Trade Route, which linked the planet Abregado-rae in the Core Worlds to the distant Outer Rim.
During the war's initial year, the Sith's navy advanced onto the Rimma super-hyperroute, effectively blockading the route by positioning the majority of its fleet within the Seswenna sector, situated near the edge of the Mid Rim. With control over the crucial and extensive hyperspace lane, the Imperials constricted Republic supply chains through a highly efficient operation that strained the Jedi defenders in the Minos Cluster and Republic forces across the Outer Rim. The repercussions that heavily burdened the Republic's defense force were also felt on the capital world of Coruscant, where the blockade contributed to widespread panic among the highest levels of galactic politics. The Republic Military eventually launched a counterattack within the Seswenna sector, but endured a devastating defeat that resulted in the capture of hundreds of Republic soldiers. Although news of the failed assault significantly demoralized other Republic forces in the Outer Rim who relied on supplies from the Rimma Trade Route, the Republic Navy's fleets managed to regroup by 3680 BBY and initiate another attack within the Seswenna region. This effort proved successful, and the Sith blockade of the trade route was broken, freeing up transport for Republic supplies to the Outer Rim Territories.
Although ultimately broken by the Republic's naval forces, the year-long blockade of the Rimma Trade Route was a highly successful undertaking, particularly in conjunction with the Imperial victory in the Sluis sector. Furthermore, it enabled the Sith to gain an early advantage over the Jedi Order in the Empire's attempt to seize the resource-rich Minos Cluster. The series of losses for the Republic compelled government leaders and the Jedi High Council to organize an emergency defense summit in an effort to organize and prioritize the galaxy's military resources. The meeting, convened by the Galactic Senate, resulted in political deadlock, as senators and other representatives refused to participate in deliberations if they believed their constituent worlds were neglected. While the political crisis persisted within the highest echelons of the Republic government, the Empire advanced to sweep the Outer Rim Territories in their widely successful war.
In 3671 BBY, a decade after their initial seizure of the Rimma Trade Route, the Empire returned to the Seswenna sector and captured the region, solidifying their dominance over much of the Outer Rim. The blockade of major hyperspace lanes became the most effective tactic in the war, especially when the Mandalorian warrior clans joined the conflict on behalf of the Empire. In 3661 BBY, the Mandalorians seized the Hydian Way; with the Mandalorian's blockade of the Hydian Way and the Sith's control of the Rimma Trade Route in the Seswenna sector, the Empire controlled two of the galaxy's most vital supply lines. The Kel Dor Jedi Knight Gnost-Dural maintained a journal during the Great Galactic War that included references to the Rimma blockade, along with his personal feelings of relief after it was initially broken in 3,680 BBY; as a Republic defender in the Minos Cluster, Gnost-Dural and his comrades depended on reinforcements and supplies that were transported along the hyperroute. Following the war's conclusion with the signing of the Treaty of Coruscant in 3653 BBY, Gnost-Dural's journal, as well as a scholarly holodocumentary produced by the Kel Dor on the early days of the war and the Rimma Trade Route blockade, were submitted to the Jedi Archives on Tython for record-keeping purposes.
The blockade of the Rimma Trade Route was conceived as part of the backstory for the 2011 BioWare video game, Star Wars: The Old Republic. The event was initially mentioned on the Sith Empire's in-universe Holonet page, published on The Old Republic website.
- The Sith Empire on The Old Republic Holonet (backup link) (content now obsolete; original version)
- Timeline 6: Onslaught of the Sith Empire on The Old Republic's official website (article) (backup link) (First mentioned)
- The Journal of Master Gnost-Dural