Take Joe, who had no real past, no comfort in the present, but whom Danpei struggled to lead towards tomorrow ("Tomorrow's Joe"). Danpei, he lost everything in the past due to not thinking about the future, and thus tried to destroy the present through his drinking, but found a way to deal with his present situation by showing Joe towards the future (but often ends up trying to protect him in the present instead). Mendoza, who had a presumably easy past (which we don't even get to see), a perfect present, and whose fighting style and attitude were all about preserving himself for a bright future (see how he always visited doctors and all), which can be said to embody the progressive and ambitious Japan that worked for a prosperous post-war society and had put WW2 and the past behind it, but who didn't understand Joe. There was the war orphan fighter, whose present was defined by the horrors of his past, but who didn't move towards a future. Or Rikiishi, who had truly had a bright present and future, but who felt he had to deal with his past, in Joe, in order to advance towards that future.