Kodansha says it had over 1,000 titles removed from the subscription program; Kobunsha reports that 550 of its titles were removed, and Shogakukan indicates approximately 180 of their titles were taken out of KU.
Bloomberg reports that "Amazon sought to renegotiate its contracts with Kodansha, Kobunsha and Shogakukan in September, and amid discussions decided to remove their titles from Kindle Unlimited." Kodansha said in a statement that, "Due to a unilateral decision by Amazon, our top-ranked titles were no longer being distributed by the company, without any notification." A spokeswoman for Kobunsha said the publisher is "asking Amazon to continue the service as defined by the current contract."
Amazon claims that "titles regularly rotate in and out of the catalog," while noting that the titles in questions are still available for sale.
In a separate Amazon item, the company announced a change in their product review guidelines that bars general product reviews provided in exchange for free merchandise -- except for those generated through their own Amazon Vine program. But books remain exempt from the broader policy: "We will continue to allow the age-old practice of providing advance review copies of books."