I did not look up but I am pretty sure JL and TG have interline agreement. However, the point you want to check with an airline (JL) is that your connection at NRT is 20 hours.

JL 9 ORD-NRT arrives at NRT on 2:30 p.m. 20 hours connection at NRT implies that your flight out of NRT is next day on TG 641 departing 10:45 a.m. This will be overnight connection at NRT.

In the U.S. airports since 9/11 the government imposed the rule that overnight connection as like in your situation passengers cannot through check the baggage, passengers have to pick up the baggage at the connecting airport and re-check next day for connecting flight all in name of security. This has nothing to do with interline agreement of airlines, it is the government rule.

I am not sure about the situation at NRT, but I do think it is worth checking with JL to see if they were allowed to through check your baggage in situation of overnight connection at NRT.