Online claims that phrases in a kanji workbook written by a teacher at major cram school Sundai include inappropriate sexual references have forced the book's publisher to consider a revised version.

The workbook, published last February, contained phrases such as, "No one should notice the intimate relationship between my professor and I," and, "I regarded the gentle slope (of her body) with awe."

It also contains phrases such as "I traced back through her life like a stalker." Some of the phrases were written in katakana so that users can write them in kanji.

"This is out of line," said a 50-year-old self-employed woman whose high school-aged daughter bought the workbook, consulted with her, and said it was disgusting.

The workbook is for high schoolers aiming for university entrance exams.

"We were looking for sentences that are memorable to the students. Female staffers had checked the phrases but we would like to look into it again," said an official at publisher Sundai Bunko.

The writer also said sections considered inappropriate should be revised. But the publisher has yet to decide when to publish a revised version.

Reading its content, a female student who attends a university in Tokyo said, "It could be funny if it's understood as a workbook (with) dirty jokes, but I wouldn't want to see that in ordinary workbooks."