Corruption of Towashi — ruling 1

Only a transforming double-faced permanent can enter the battlefield "transformed," and only if it enters with its back face up. Notably, melded permanents can't enter transformed, and modal double-faced permanents can't enter transformed, even if they enter with their back faces up.

Corruption of Towashi — ruling 2

Similarly, only transforming double-faced permanents (including transforming double-faced cards and Incubator tokens) can transform. A face-up permanent turning face down doesn't count as transforming, nor does a face-down permanent turning face up.

Corruption of Towashi — ruling 3

The last ability of Corruption of Towashi will trigger if a permanent you control transforms in either direction, going from front face up to back face up or vice versa.

Corruption of Towashi — ruling 4

Once you've chosen to draw a card because of the last ability (which is likely as soon as possible, but there may be situations in which you don't want to draw immediately), that ability will stop triggering for the duration of that turn.

Corruption of Towashi : règles, fonctionnement et interactions (MTG)

Corruption of Towashi is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

When this enchantment enters, incubate 4. (Create an Incubator token with four +1/+1 counters on it and ": Transform this token." It transforms into a 0/0 Phyrexian artifact creature.) Whenever a permanent you control transforms or a permanent you control enters transformed, you may draw a card. Do this only once each turn.

How it works : Corruption of Towashi

Original English text — Wizards of the Coast / Scryfall

#1April 14, 2023· Wizards of the Coast
Only a transforming double-faced permanent can enter the battlefield "transformed," and only if it enters with its back face up. Notably, melded permanents can't enter transformed, and modal double-faced permanents can't enter transformed, even if they enter with their back faces up.
No other card is named in this ruling.
#2April 14, 2023· Wizards of the Coast
Similarly, only transforming double-faced permanents (including transforming double-faced cards and Incubator tokens) can transform. A face-up permanent turning face down doesn't count as transforming, nor does a face-down permanent turning face up.
No other card is named in this ruling.
#3April 14, 2023· Wizards of the Coast
The last ability of Corruption of Towashi will trigger if a permanent you control transforms in either direction, going from front face up to back face up or vice versa.
No other card is named in this ruling.
#4April 14, 2023· Wizards of the Coast
Once you've chosen to draw a card because of the last ability (which is likely as soon as possible, but there may be situations in which you don't want to draw immediately), that ability will stop triggering for the duration of that turn.
No other card is named in this ruling.