Qi Xuansu had once wondered why they did not use a Yin-Yang Gate to bring Toyotomi Hidemochi directly to the army camp. Upon reflection, the reason was simple—the distance was too great. It would require multiple transfers to reach the camp from Hikone Castle.0

The Daoist Order would have had to station multiple Diviners along the way to relay Toyotomi Hidemochi to the army camp. If anything went wrong at any point, like assassins targeting the stationed Diviners along the way, Toyotomi Hidemochi could end up stranded. In the current chaotic and contested landscape, there was also a real risk of falling into the hands of the Sonno-joi faction, adding further uncertainty.0

Moreover, setting up the Diviners in advance to relay through the gates would take time. The Daoist Order had made the decision to install the new Kampaku in haste, so time was precisely what they lacked.0

Thus, the Daoist Order ultimately abandoned the relatively safer Yin-Yang Gate method. Of the remaining land, sea, and air routes, the air route was the most conspicuous but also the fastest. Thus, using the Yinglong Warship as a mode of transport became the natural decision.0

That said, the principle behind the Yin-Yang Gate was to travel through...0