Test Sheets for Teachers in JHS 1 2 3! - Free student test sheets and reviewers for mid-term and monthly exams in public schools 先生と生徒のために中学校問題集・社会・数学・理科・英語・一学期・二学期・三学期 Note: Site in Japanese. All PDF files are not printable.
Really Learn English - Tips, lessons, articles, and exercises on English grammar and vocabulary.
Altopedia - "Sharing a little, gaining 'choco'" A must check out page for ALTs and JTEs.
Reddit : Teaching in Japan - A place to discuss the various aspects related to teaching strategies in Japan whose main focus is to provide space for teachers to discuss various aspects of their jobs and industry in greater depth