this is a horrible program. he doesn't run a 2:10 because of this training but despite this training. it is the result of a mentality based on iron will and the highest work ethic. but it is neither efficient nor produces unrivaled results. sorry. maybe he'll run strong ultra races with it.
The Japanese produce better marathoners on the whole than the US, with way more depth. This training is within the normal range of Japanese marathon training, and produces great results.
With this training this guy, who has a 14:09 PR, has run 2:09:52.
Other Japanese guys with modest 5000 PRs (in the Walmsley range) have run as fast as 2:06:xx like Inubushi and Takaoka.