Rulings
Q1: If an effect places a card under this card while it already has one or more cards under it, in what order do I place the cards?
You place it at the bottom of the cards.
Q2: A level 5 Taomon attacks, and this card's Your Turn effect triggers. At such times, if another effect digivolves the attacking Digimon into a level 6 Sakuyamon, what is the cost of the Option card that can be activated using this card's Your Turn effect?
6 cost or less. The level of the attacking Digimon is referenced during the timing when this card's Your Turn effect activates.
Q4: If I use this card's Your Turn effect to use an Option card from under this card, what happens to that Option card?
As with the standard rules, a used Option card is temporarily treated as not being in any area. After using it and activating the Option card's Main effect, the card is trashed unless it's to be placed in an area.
Data Sources
Rika Nonaka ST22-07 R [Start of Your Main Phase] [On Play] By placing 1 Option card with the [Onmyōjutsu] or [Plug-In] trait from your hand under this Tamer, <Draw 1> and gain 1 memory. [Your Turn] When one of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in its name attacks, by suspending this Tamer, you may use 1 [Onmyōjutsu] or [Plug-In] trait Option card with as high or lower a use cost as that Digimon's level from under this Tamer without paying the cost. --- [Security] Play this card without paying the cost.
Rika Nonaka ST22-07 R [Start of Your Main Phase] [On Play] By placing 1 Option card with the [Onmyojutsu] or [Plug-In] trait from your hand under this Tamer, <Draw 1> and gain 1 memory. [Your Turn] When one of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in its name attacks, by suspending this Tamer, you may use 1 [Onmyojutsu] or [Plug-In] trait Option card with as high or lower a use cost as that Digimon's level from under this Tamer. --- [Security] Play this card without paying the cost.
Rika Nonaka ST22-07 R [Start of Your Main Phase] [On Play] By placing 1 Option card with the [Onmyōjutsu] or [Plug-In] trait from your hand under this Tamer, <Draw 1> and gain 1 memory. [Your Turn] When one of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in its name attacks, by suspending this Tamer, you may use 1 [Onmyōjutsu] or [Plug-In] trait Option card with as high or lower a use cost as that Digimon's level from under this Tamer without paying the cost. --- [Security] Play this card without paying the cost.
牧野留姫 ST22-07 R 【自分のメインフェイズ開始時】【登場時】自分の手札から、特徴に「陰陽術」/「プラグイン」を持つオプションカード1枚をこのテイマーの下に置くことで、≪1ドロー≫し、メモリー+1。 【自分のターン】名称に「レナモン」/「キュウビモン」/「タオモン」/「サクヤモン」を含む自分のデジモンがアタックしたとき、このテイマーをレストさせることで、このテイマーの下から、使用コストがそのデジモンのLv.の数値以下の特徴に「陰陽術」/「プラグイン」を持つオプションカード1枚をコストを支払わずに使用できる。 --- 【セキュリティ】このカードをコストを支払わずに登場させる。