To find the exact paper you need, try searching academic databases like Google Scholar for: "2channel" AND "corpus" AND "Japanese" "text mining" AND "2ch.net" "sentiment analysis" AND "anonymous forum data"
In data science and computational linguistics, researchers often use large-scale archives of 2ch (frequently distributed as .rar or .7z files) to study: 2ch.rar
If you have a from the paper or know the author's name , please share it so I can find the exact document for you. To find the exact paper you need, try
: This type of research often uses 2ch data to categorize user behaviors without individual identities. 2ch.rar