Wash all of your sweet potatoes thoroughly (especially the ends where there may be dirt on it). I like to scrub with a brush to get all of the dirt off.

Without drying off the sweet potatoes (since it adds moisture) wrap the sweet potatoes in a paper towel and quickly run water over the paper towel again to make it wet. If it's DRIPPING with water, I recommend lightly wringing it out just enough so that you don't have a puddle of water.

Wrap the wet sweet potato and paper towel in a large piece of aluminum foil so that the sweet potato is completely covered.

Place the Japanese sweet potatoes onto a baking dish and place it into your oven.

Turn on your oven and set it to 160C or 320F. While your oven heats up with the sweet potatoes inside, it will give your sweet potatoes a good enough time to stay in the 65C - 80C range and get them EXTRA sweet!

Once your oven has preheated, set your timer for 90 minutes.

After 90 minutes, leave your sweet potatoes in the oven for at least 30 minutes to let it cool down to the ideal range again. This step is crucial in ensuring you get a silky smooth baked Japanese sweet potato.

Once your Japanese sweet potatoes are cool enough to touch, you are ready to enjoy!

さつまいもをしっかり洗う（特に端の部分の汚れをブラシで落とす）。

水気を拭かずにそのままキッチンペーパーで包み、さらに水で湿らせる。 ※ 水が滴るほどではなく、軽く絞る程度がベスト。

湿らせたキッチンペーパーごと、アルミホイルでしっかり包む。

天板にのせ、オーブンに入れる。

オーブンを160℃（320℉）に設定し、予熱と同時に加熱開始！

予熱完了後、そのまま90分焼く。

焼き上がったらオーブンの中で30分ほど放置し、じっくり冷ます。