Chinese Hearthstone Server Rollback Reveals How Cards Are Picked

Published: January 19, 2017 2:52 PM /


Blizzard China Hearthstone Splash

Blizzard China issued an apology (translated here) yesterday to China's Hearthstone players, as they came to the decision to rollback the China Hearthstone servers to 4 days ago. The apology came after an extended server downtime that lasted for over 30 hours. Blizzard China explained that a power failure had occurred at the server's data center the previous Saturday at 3:14 pm (Beijing time) that corrupted data from that point on. The Hearthstone servers then continued to operate until the following Tuesday, before the servers brought offline. The decision was made to rollback the server to a point prior to the data corruption, which meant that any gold, dust or cards obtained after that point no longer exists.

While there was the usual grumbling about lost progress and rare cards, Chinese Hearthstone players were surprised to find a very curious pattern emerging when they went through the whole process of re-opening compensation packs.


Hearthstone pre-rollback Gold Legendary
Pre-rollback gold Legendary Raza the Chained | Credit to: jayshawww

Hearthstone post-rollback Gold Legendary
Post-rollback gold Legendary Don Han'cho | Credit to: jayshawww

Players have found that they are re-receiving cards of the same rarity in the same number of packs, as they did previously. This would be hard to prove as it is not common to record all the cards you would open and their rarity and frequency so comparison pre and post rollback would be near impossible. However, quite a few people had opened Legendary and even Gold Legendary cards prior to the rollback, and had kept screenshots of their lucky finds.

Referring to the above user jayshawww's screenshots: Prior to the rollback he had opened a Gold Legendary Raza the Chained which he then lost after the rollback. When re-opening the packs again, he received a Gold Legendary in about the same number of packs it took to receive his Gold Don Han'Cho. Also, note that the two card packs have the same number of cards of each rarity overall.

The chances of receiving a random Gold Legendary is approximately 0.10%, and the chances of getting another Gold Legendary in the same number of packs would be even lower. It is also unlikely to be an isolated fluke, as many other users have reported receiving the same supposedly 'random' re-drops.

hurricanevenus11 pre rollback Gold Legendary
Pre-rollback Legendary Lorewalker Cho and gold Legendary Malygos | Credit to: hurricanevenus11

hurricanevenus11 post rollback Gold Legendary
Post-rollback Legendary Sylvanas and gold Legendary Cairne | Credit to: hurricanevenus11

A more conspicuous example is that of hurricanevenus11's drops. Prior to the rollback, he received 2 Legendaries in a single pack - a regular Lorewalker Cho and a gold Malygos. Post-rollback, he received two Legendaries in a single pack again - a regular Sylvanas and a gold Cairne. Similar to jayshawww, both packs had the same number of rarities - 2 Legendaries, 1 Rare, 2 Commons.

There are many theories and opinions currently circulating based on these anecdotal user screenshots and posts, which are all technically unverified. However, assuming that most are truthful, there has been several patterns observed that shed some light on how card drops are calculated in Hearthstone.

  1. Proportion of card rarities in a pack are predetermined; but the actual cards are not
  2. Card drops are tied to specific card sets
    • E.g. if you had a Legendary drop from a Classic Set pack, you need re-open another Classic Set pack to have it drop again
  3. Speculated separate hidden 'card pack quotas' for each card set
    • E.g. a player buys 5 packs from the Classic Set, and may be guaranteed an Epic card on the 5th pack he opens.

It should be noted that the current theories about card drops does not contradict Brode's previous statements about card drops, at least not entirely.The re-opening of packs actually prove them to be more or less true; cards are randomly chosen from a pool that is limited by the pre-determined rarity for that card drop.

That this situation has happened in China has also interesting implications, as China's Ministry of Culture has passed regulation that requires developers to disclose the probabilities of winning virtual items, and this will come into effect by May 1st 2017. With that in mind, how will Blizzard display the probabilities of Hearthstone card drops, and even in Overwatch lootboxes? Time will tell.

How does knowing a bit of how card drops are determined make you feel? Are you okay with the current system of card drops or would prefer true total RNG? Let us know in the comments below!

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Sam Ooi
| Staff Writer

Ex-game-studio grunt, now freelance writing and floating around. Just don't ask me about what I have seen~

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March 11, 2014 (Calendar)