Chiriyakhana is based on Sharadindu Bandopadhyay's famous detective novel of the same name. There was many a deviation from the novel just like the case in Ray's some other cinematic adaptations. The biggest one being, in the movie Byomkesh (the sleuth) is bachelor, his 'Watson' Ajit is married. During the movie events Byomkesh is shown to be living in a "mess bari". Ajit stays with him since his wife is out in Ghatsila. Secondly, the murders took place with a 'blunt instrument' (Ray's fascination with blunt instrument was also evident in some of his own detective stories with 'Feluda', namely 'Hatyapuri'). Also, in the movie Byomkesh is shown to wear disguise twice, none so was in the novel. Movie character Byomkesh has a pet baby python, keeps a human skeleton in his room and has no problem drinking scotch in the evening. Book character was fairly lazy to own a pet, too cerebral to actually study anatomy and in spite of being a habitual smoker, never drank. Not that I mind the cinematic deviations, but there should be a strong logic behind each. While I can understand the room being too drag without the skeleton and the snake -- I cannot get the point of Byomkesh being single. May be Ray's ideal sleuth was tall, cerebral and deliciously single as we see later in form of "Feluda".
Uttamkumar is just about average as Byomkesh. There are two weaknesses that would draw a lot of attention today. His mimic of a Japanese horticulturist is too over the top and secondly, his character was needlessly rough with the characters of the farm from very beginning.
Overall, this is one of Ray's average movies. It's surprising that this was awarded the best picture in 1967 in India and Uttam won the "Bharat" (India's then version of Oscar for best actor) award for his role.