(Reuters) - A federal judge in Chicago wants attorneys at global law firm Dentons to explain their request to withdraw as counsel to a Japanese pachinko billionaire who is embroiled in a multi-million dollar legal fee fight with litigation firm Bartlit Beck. During a Tuesday hearing, U.S. District Judge John Kness gave Dentons until Jan. 18 to elaborate on what the firm called an "irretrievable breakdown" in its relationship with embattled casino entrepreneur Kazuo Okada. The firm on Dec. 17 asked Kness for permission to withdraw, but didn"t say why its relationship with Okada soured, citing attorney-client privilege. Kness said Dentons" reliance on that privilege is "a little overstated." "I don’t think you can come in and give me no reason," Kness said. He said he would allow Dentons to explain its reasons in a sealed brief, but the firm must justify the need for confidentiality. Alex Gude, a partner at Dentons affiliate Dentons Bingham Greenebaum, told Kness he did not know whether Okada has retained new counsel. Dentons" motion to withdraw is opposed by Bartlit Beck, which has been locked in litigation with Okada since 2018 over a $50 million legal fee Okada allegedly owes to the Chicago-based litigation firm. Okada hired the firm for a legal fight between his Universal Entertainment Corp and Wynn Resorts Ltd, which ended in a $2.6 billion settlement. An arbitration panel awarded Bartlit Beck $50 million by default in 2019 after Okada stopped participating in the proceedings. Kness approved the award last March. Okada and Dentons have appealed Kness" ruling to the 7th Circuit U.S. Court of Appeals, which is still pending. Bartlit Beck says it has been trying to conduct discovery on Okada"s assets in multiple court venues and that the award has now ballooned to $63 million with interest. The firm accused Dentons of "further enabling Mr. Okada’s strategy of delay" by withdrawing as his counsel. Dentons has said Bartlit Beck is engaged in "unfounded speculation" about its motives. Attorneys for both Bartlit Beck and Okada did not respond to requests for comment. The case is Bartlit Beck LLP v. Okada, U.S. District Court for the Northern District of Illinois, No. 1:19-cv-08508. For Bartlit Beck: Joshua Ackerman and Adam Hoeflich of Bartlit Beck; and Sean Berkowitz of Latham & Watkins For Kazuo Okada: Alex Gude and Meaghan Klem Haller of Dentons Bingham Greenebaum; and Robert Richards of Dentons US