四一式山砲 (Type 41 Mountain gun ) 外装タ弾 (exterior loaded HEAT)
Type 41 Mountain gun that fires 200mm HEAT round with 300mm of penetration.
Ammunition Stat
Weight: 19.77 kg
Length 902.4mm
Diameter: 200mm
Penetration: 300mm
Explosive weight: 6.25kg
Velocity: 90m/s
Source: 研究事項ニ関スル綴〔内容明細裏面〕
PDF page: 141
Unfortunately I can’t find picture of it.
But I guess it has similar concept as Pak 36 with Stielgranate 41.
Edit:
80mm exterior loaded heat round with 100mm pen for Type 94 37 mm anti-tank gun.
It might give some insight on how the 200mm exterior loaded heat round might look like.
Picture source.