Bad question. Neither duration nor seasonality intrinsically define the other; focusing on that ignores the menu of real economic strategies.
Here in Japan, low season is a fluid concept, often disrupted by national holidays like Obon or Golden Week, regardless of whether your trip lasts one or two weeks.
What matters is finding a detour, such as shoulder seasons or last-minute offers, which can offer the best compromises.
A two-week trip during the cherry blossom peak remains expensive, even if you think you've "limited the duration".
It is always necessary to look beyond the raw duration and consider specific local events.