On the Men's side, it's fairly simple & unambiguous. Men's tennis events for the season are classified into 3 tiers. ATP Masters 1000, ATP 500 & ATP 250 in decreasing order of importance based on points.
However, on the Women's side, there seems to be 3 tiers but the events are classified as WTA Premier & WTA international in decreasing order of importance based on points. But at this point it gets ambiguous. Taking into account the recent tournaments, WTA Tokyo(concluded today) & WTA Wuhan(starting today) are listed as WTA Premier events. But WTA Tokyo awards 470 points while WTA Wuhan awards 900 points.
So how can I unambiguously classify WTA events based on tiers? Also please list all the WTA events in a season which are Tier 1(900 points events)