Tsukishima Hiroshi, Heian jidai no kanbun kundoku ni tsuite no kenkyū (Tokyo University Press, 1963)
This work comprehensively and systematically explains the earliest forms seen in  the glossing of literary Sinitic (kanbun kundoku), which facilitated the negotiation between ancient Japanese words and literary Sinitic. It does so based on the organization of a vast number of sources and also broaches individual works. It can be used as a dictionary for kundoku because of its detailed vocabulary list.

Kamei Takashi et al., ed., Nihongo no rekishi (Heibonsha, 6 volumes and bekkan, 1963-1966, Heibonsha Library Version 2006-2008)
Taking Japanese from a historical perspective, this work gives a concrete outline and theorizes both literature and social history. The explanatory sections (kaisetsu) in the Heibon Library version of each volume are required reading that speak to the critical appraisals and saliant points worth remembering from when it was published half a century ago (unfortunately many libraries are now disposing of this version).

Haga Norio, Man’yōshū ni okeru chūgoku juyō (Hanawa shobō, 2003)
The scope of this work, evinced by its thoroughness and the overwhelming originality of its examinations and observations, addresses ancient literature as it has been constructed by the study of the East Asian classics. It also speaks to methodology and important points for texts as well as a range of issues that should be pursued. There is also a comprehensive and exhaustive section called “Various Problems in Reception of the Classics.”

Saitō Mareshi, Kanbunmyaku no kindai: shinmatsu meiji no bungakuken (Nagoya daigaku shuppankai, 2005)
In order to revise our view of the classical world, we need to investigate the words that we take to be self-evident, the various modern notions of the classics, and the genealogy of the problems themselves. This work pauses to adopt this perspective, excavates concrete issues and problems, and indicates a rough sketch for new pursuits. There is also Kanji sekai no chihei: watashitachi ni totte moji towa nanika (Shinchōsha, 2014) by the same author.

Kōnoshi Takamitsu, Kanji tekisuto to shite no Kojiki (Tokyo University Press, 2007)
Its uncompromising investigation of the nature of the Kojiki opens with understanding the world of letters as a base and ends up overturning issues that have up to now restricted our literary understanding. Along with understanding the Kojiki itself, it also discusses the state of Kojiki scholarship. Man’yōshū o dō yomu ka: uta no hakken to kanji sekai (Tokyo University Press, 2013) is by the same author.

Tokyo daigaku kokubun kanbungakubuka, ed., Koten nihongo no sekai: kanji ga tsukuru nihon (Tokyo University Press, 2007)---. Koten nihongo no sekai 2 (Tokyo University Press, 2011)
The title accurately describes the content of these two texts. They raise and pursue problems according to the facts in a period-by-period format, and attempt to anticipate new developments that are hinted at by considering these issues in their entirety. The work is targeted at undergraduates, but by checking the notes and references, it also suggests how one should approach a particular issue.