Go Battle League Legendary Rate - Interlude Season

Update 3 – 3/17/2022 17:40 UTC:

Throughout Tapu Koko’s availability in GBL, we observed 182 encounters, 2 of which were Tapu Koko. This now leads us to the two-sided 99% confidence interval for Tapu Koko’s rate being 0.06% to 5%. Since the switch over to Tornadus’ Therian forme, we have observed 63 GBL encounters, 5 of which were Tornadus Therian Forme (99% confidence interval of 2% to 21%). At present, we cannot say with certainty that legendary rate has increased (Fisher’s exact test p-value = 0.013), but we will continue to monitor the situation.

Update 2 – 3/14/2022 05:30 UTC:

We have now had a total of 158 encounters examined at Rank 20, and of those encounters, 1 featured Tapu Koko. Assuming there have been no adjustments, this suggests with 99% confidence that as of the time of writing, the Legendary rate for this season is no higher than 4.13%.

Update 1 – 3/11/2022 23:30 UTC:

We have now had a total of 101 encounters examined at Rank 20, and of those encounters, 0 featured Tapu Koko. This now suggests with 99% confidence that as of now the Legendary rate for this season is no higher than 4.5%.

Greetings, Travelers!

Those familiar with Go Battle League (GBL), the online player-versus-player part of Pokémon Go, know that after reaching Rank 20, the current Tier 5 Raid Boss is available as an encounter if you’ve won 3 matches in a set (or 1 match on the Premium track). These chances at legendaries are a major incentive for some battlers to get to Rank 20 as quickly as possible. Data from the latter half of 2021 (GBL seasons 8-9) showed that Legendaries made up 28% of GBL encounters at rank 20 and above. In Season 10, Niantic announced that Legendaries encountered in GBL would be easier to catch, but they lowered the encounter rate to 16%.

Niantic’s initial announcement of the current GBL season described it as an “Interlude Season,” rather than “Season 11”. This meant no visible battle ratings, and no ability to rank up past Rank 20. As usual, the season announcement came with a list of encounters, as well as the ranks at which they become available, and as expected, this announcement stated that at Rank 20, players would be able to receive the current Tier 5 legendary raid boss as an encounter reward.

However, based on what we’ve seen and heard across several different avenues, the lightning-wielding guardian deity of Melemele Island has been surprisingly absent as an encounter. The Silph Science and Research Server immediately delved into the issue, and thanks to a group of highly passionate battlers, we examined 67 encounters at rank 20. Of those encounters, 0 featured Tapu Koko. While it is possible that we just haven’t found one yet, that would indicate a significantly lower legendary rate than what we’ve seen in previous seasons, and with 99% confidence, our data suggests this season’s legendary rate is no higher than 7%.

The release of Tapu Koko already had seen some issues, with some battlers getting lucky and encountering it as a reward encounter in Go Battle League last season, even before it arrived as a raid boss, but it seems to be almost absent since the new season started. Could this be another bug associated with the Alola region rollout, or is this linked to Niantic development testing as part of the Interlude Season?

Until next time, Travelers!


Author: Scientist PhoenixCrystal7
Analysts: Scientist PhoenixCrystal7, Scientist CaroKann, Senior Researcher FatalisticFeline
Project Leads: Scientist DarkMighty, Lead Researcher EagleTJM, Lead Researcher Jyagaimasu
Graphic Artists: Scientists WoodWoseWulf and CaroKann
Editors: Lead Researcher JinianD and Senior Researcher Forge

The following trainers were able to consistently win 3 matches or more per set at Rank 20:

  • PhoenixCrystal7
  • Lilwinery
  • Burns224
  • otarie
  • ziller
  • kroxldyphivc
  • Red8192
  • Anthony
  • tfos11
  • Ritesh
  • bananadado
  • Ieyasu
  • dstritt15
  • Jet
  • Ruijifu
  • DrtyMorty