Period Basis is shared between Goonswarm, and Zenith Affinity. It has a handful of R64 moons and quite a few systems with high numbers of belts, but it lacks the perfect truesec that exists throughout Delve.
Both Period Basis and Delve can spawn Blood Raider commanders.
BoB took Period Basis when they moved to the south and for a while only owned it and Delve before they went to war with Firmus Ixion and took control of Querious. Eventually, Period Basis became home to several BoB pet alliances including Mercenary Coalition. Just prior to Goonswarm's first invasion of Delve, Mercenary Coalition and several other pet entities split from BoB and formed Tortuga, which quickly established control of the region's stations except for BoB-owned TPAR, which became the site of several fierce battles. Tortuga briefly allied itself with the RSF but failed to help the war effort and was eventually reset. After BoB regained control of all of Delve and Querious they turned their attention back to Period Basis and quickly retook the region. They then established several other pet alliances in the region, most notably including Frontal Impact and Executive Outcomes. In the second invasion of Delve KIA, Morsus Mihi, and Zenith Affinity focused on taking control of Period Basis. There was apparently much indecision amidst the GBC leadership concerning whether or not they should even fight for Period Basis beyond trying to save BoB's R64s in the region. Eventually they did try to save the key stations in the south and west of Period Basis but were repeatedly defeated by coalition fleets lead by Imperian of Morsus Mihi.
Period Basis was initially divided as shown on the following map. Goonswarm shares ratting rights in the Goon-owned X0V7-5 and N-39FI constellations with Zenith Affinity.
- E2-RDQ (Minmatar refinery outpost, 35% refine) - Zenith Affinity
- GR-J8B (Amarr factory outpost) - Zenith Affinity
- TN-25J (Minmatar refinery outpost, 35% refine) - Zenith Affinity
- 1-NJLK (Gallente office outpost) - Zenith Affinity
- EIMJ-M (Caldari research outpost) - Zenith Affinity
- L5D-ZL (Amarr factory outpost) - Zenith Affinity
- Y-CWQY (Minmatar refinery outpost, 35% refine) - Zenith Affinity
- TPAR-G (Gallente refinery) Goonswarm
- PA-VE3 (Amarr factory outpost) - Zenith Affinity
- G-Q5JU (Gallente outpost) - Zenith Affinity
- Z-M5A1 (Minmatar refinery outpost) - Zenith Affinity