I had recently seen two examples of a foot sweep (de ashi barai) used in a kendo match to fell an opponent before striking them:
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| 2018 All Japan Police Team Championship Final | 2014 National Police Kendo Tournament (First Division) |
Is this a legal move? If so, what other types of throw are legal?
I have not found an authoritative set of rules for Kendo (odd, to me, but maybe I'm using the wrong search terms) other than this brief set that mention no tripping or shoving opponents out of bounds, but the footage your provide is from a "Police Kendo" match, where they apparently specifically allow a broader variety of techniques. This discussion on Reddit claims that body checks and striking a downed opponent are legal in regular Kendo, and that the Police and Imperial Guard (I think they call it tokuren) run their own competitions with foot sweeps being legal.
Just to add some sources:
I can't find a freely accessible copy of the FIK's Regulations Of Kendo Shiai and Shinpan, but it appears most local rulesets based off of this1 2 3 prohibit foot sweeps (though body checks appear to be permitted under some rules if performed to instigate a technique):
(Miscellaneous and Prohibitive acts)
...
2. Tripping up or sweeping the opponent’s legs from under them
3. Unfairly shoving or pushing an opponent outside the court with no attempt to preform a technique;