Ryo arrives in Hong Kong at the end of February according to non-save transfer files. That gives us three months since the murder of Iwao. Assuming Ryo stayed in Hong Kong and Kowloon for a month each, this puts us at the end of April.
Where am I going with this? Iwao's birthday is the third of May.
In other words, just in time for Shenmue III.
Assuming Ryo gets to Guiin before May, we will experience Ryo's regret and depression as his father birthday passes. I truly feel it may be the most heart breaking moment in the series so far and it's too juicy of a story to pass up. How do you expect Ryo to react, Dojo? I'm really hoping this is the case so we can see Ryo grow.