No one has mentioned it yet, but game 5, the point at 10-7 SYS ball clips the net causing Ito to miss her FH. No apology from SYS (at least not seen on ITTV stream, maybe Japan TV had a different angle to capture that in case SYS did apologize for the net ball.)
From that point onwards, Ito's BH and serves (her strengths IMO) lets her down. She losses the 10-8, 10-10 and 10-11 points on missed BHs, none of which are particularly difficulty to make except for the weight of her countries expectations on her shoulders. She misses proper contact on her 10-9 serve and that ball sits up high with poor ball length for an easy SYS BH winner down the line.
Ito played well but in typical CNT fashion, SYS played much more disciplined and in better control of herself in the end.